Q.1 Which component in a powered wheelchair converts battery DC voltage to the AC voltage needed by the motor?
Transformer
Inverter
Rectifier
Regulator
Explanation - An inverter changes the low‑voltage DC from the battery into the higher‑frequency AC required to drive the wheelchair's motor.
Correct answer is: Inverter
Q.2 What is the primary purpose of a sip‑and‑puff interface in a communication aid?
Detecting eye movement
Measuring heart rate
Translating breath patterns into control signals
Providing auditory feedback
Explanation - Sip‑and‑puff devices sense inhalations and exhalations and convert them into electronic commands for users who cannot use their hands.
Correct answer is: Translating breath patterns into control signals
Q.3 Which type of sensor is most commonly used to detect wheel slippage in a powered mobility scooter?
Hall‑effect sensor
Accelerometer
Gyroscope
Load cell
Explanation - Hall‑effect sensors placed near the motor or wheel can detect changes in magnetic field caused by wheel rotation speed variations, indicating slippage.
Correct answer is: Hall‑effect sensor
Q.4 In an eye‑tracking communication system, the term 'fixation' refers to:
The speed of eye movement
A brief pause on a target area
The total number of saccades per minute
The calibration process
Explanation - Fixation is when the eye remains relatively still on a specific point, allowing the system to register a selection.
Correct answer is: A brief pause on a target area
Q.5 Which battery chemistry is most widely used in modern powered wheelchairs due to its high energy density and low weight?
Lead‑acid
Nickel‑Cadmium (NiCd)
Lithium‑Ion (Li‑Ion)
Alkaline
Explanation - Li‑Ion batteries provide more energy per kilogram and have longer life cycles, making them ideal for lightweight mobility devices.
Correct answer is: Lithium‑Ion (Li‑Ion)
Q.6 A Bluetooth Low Energy (BLE) module in a communication aid primarily benefits the user by:
Increasing processing speed
Reducing power consumption during wireless data transfer
Providing higher audio fidelity
Enabling wired connectivity
Explanation - BLE is designed for low‑power applications, extending battery life while maintaining wireless communication.
Correct answer is: Reducing power consumption during wireless data transfer
Q.7 Which of the following is a key advantage of using a modular design for a prosthetic knee joint?
Higher cost per unit
Easier customization and repair
Reduced mechanical strength
Limited range of motion
Explanation - Modular components can be swapped or adjusted to fit different users, simplifying maintenance and personalization.
Correct answer is: Easier customization and repair
Q.8 In a speech‑generating device (SGD), the term 'vocoder' refers to:
A hardware battery pack
A software algorithm that synthesizes speech from text
A type of wireless antenna
A mechanical switch
Explanation - A vocoder converts digital text or symbols into audible speech by shaping sound waveforms.
Correct answer is: A software algorithm that synthesizes speech from text
Q.9 What is the function of a CAN bus in a powered wheelchair’s control system?
Provide high‑speed video streaming
Allow multiple microcontrollers to communicate over a single wiring harness
Charge the battery
Control the user interface lighting
Explanation - The Controller Area Network (CAN) bus enables reliable, real‑time communication between various electronic modules in the wheelchair.
Correct answer is: Allow multiple microcontrollers to communicate over a single wiring harness
Q.10 Which type of actuator is commonly used for adjusting the height of a standing frame for individuals with mobility impairments?
Pneumatic cylinder
Hydraulic piston
Electric linear actuator
Rotary stepper motor
Explanation - Electric linear actuators provide precise, smooth vertical motion and are easier to control electronically.
Correct answer is: Electric linear actuator
Q.11 In the context of assistive communication devices, what does the term 'predictive text' mean?
The device guesses the next word based on previously entered characters
The device records the user’s speech for later playback
The device uses GPS to locate the user
The device encrypts messages for security
Explanation - Predictive text algorithms reduce typing effort by suggesting likely next words, speeding up communication.
Correct answer is: The device guesses the next word based on previously entered characters
Q.12 Which standard defines the communication protocol for medical device networking that can also be used in rehabilitation equipment?
IEEE 802.11
HL7
ISO 9001
CANopen
Explanation - Health Level Seven (HL7) provides a framework for exchange, integration, and retrieval of electronic health information, applicable to rehab devices.
Correct answer is: HL7
Q.13 A joystick used for controlling an electric wheelchair typically incorporates which type of feedback to improve user control?
Visual LED indicators
Haptic vibration
Audible beeps
Thermal heating
Explanation - Haptic feedback provides tactile cues about joystick position or system alerts, aiding precision.
Correct answer is: Haptic vibration
Q.14 Which of the following is a major safety feature required on powered mobility devices to prevent tip‑over?
Speed limiter
Anti‑tip sensor and automatic braking
Bluetooth connectivity
Voice command activation
Explanation - Sensors detect excessive tilt and trigger brakes or reduce speed to avoid overturning.
Correct answer is: Anti‑tip sensor and automatic braking
Q.15 In a head‑mounted switch system, the switch is typically activated by:
Eye blink detection
Jaw movement
Head tilt beyond a preset angle
Nose pressure
Explanation - Head‑tilt switches use accelerometers or inclinometers to sense when the head exceeds a certain angle, generating a control signal.
Correct answer is: Head tilt beyond a preset angle
Q.16 What is the role of a microcontroller in a smart cane for visually impaired users?
To store large video files
To process sensor data and control vibration alerts
To provide Wi‑Fi internet access
To power the cane’s LED lights directly
Explanation - The microcontroller receives input from ultrasonic or infrared sensors and triggers haptic feedback to warn of obstacles.
Correct answer is: To process sensor data and control vibration alerts
Q.17 Which communication protocol is most suitable for low‑power, short‑range data exchange between a wearable EMG sensor and a prosthetic hand controller?
Wi‑Fi (802.11n)
Zigbee
Ethernet
USB
Explanation - Zigbee offers low power consumption, mesh networking, and sufficient data rates for EMG signals over short distances.
Correct answer is: Zigbee
Q.18 A powered exoskeleton that assists walking typically uses which type of control strategy?
Open‑loop control
Closed‑loop feedback control using force sensors
Time‑division multiplexing
Frequency modulation
Explanation - Sensors measure user intent and ground reaction forces, allowing the exoskeleton to adapt its assistance in real time.
Correct answer is: Closed‑loop feedback control using force sensors
Q.19 Which parameter is most critical when selecting a motor for a stair‑climbing wheelchair?
Motor voltage rating
Peak torque output
Number of windings
Color of the motor housing
Explanation - Climbing stairs requires high torque to overcome the weight of the wheelchair and user against gravity.
Correct answer is: Peak torque output
Q.20 In a tactile display used for communication, each raised pin corresponds to:
A pixel in a visual image
A phoneme of speech
A Braille dot pattern
A sound frequency
Explanation - Tactile displays often present Braille characters by raising pins in the standard 6‑dot configuration.
Correct answer is: A Braille dot pattern
Q.21 What is the primary benefit of using regenerative braking in electric mobility scooters?
Increasing top speed
Extending battery life by recapturing kinetic energy
Reducing noise levels
Improving wireless connectivity
Explanation - Regenerative braking converts kinetic energy during deceleration back into electrical energy, recharging the battery.
Correct answer is: Extending battery life by recapturing kinetic energy
Q.22 Which type of feedback is most useful for a user operating a myoelectric prosthetic hand?
Visual LED indicators
Audible beeps
Force feedback via vibrotactile actuators
Temperature sensors
Explanation - Vibrotactile feedback can convey grip force information, helping the user modulate grasp strength.
Correct answer is: Force feedback via vibrotactile actuators
Q.23 A wireless charging pad for a powered wheelchair uses which principle to transfer energy?
Inductive coupling
Capacitive coupling
Resistive heating
Thermal conduction
Explanation - Inductive charging relies on magnetic fields generated by a coil in the pad to induce current in a coil in the device.
Correct answer is: Inductive coupling
Q.24 In a wheelchair joystick, a ‘dead zone’ refers to:
A region where small movements do not produce motion
The maximum speed setting
A safety lock that disables the joystick
A diagnostic error code
Explanation - The dead zone prevents unintentional movement due to slight joystick deviations or tremors.
Correct answer is: A region where small movements do not produce motion
Q.25 Which sensor type is best suited for detecting obstacles in front of a robotic wheelchair?
Thermocouple
Ultrasonic range finder
Hall‑effect sensor
Photodiode
Explanation - Ultrasonic sensors emit sound waves and measure echo time to calculate distance to obstacles.
Correct answer is: Ultrasonic range finder
Q.26 When designing a speech‑output AAC device, why is a low‑latency audio codec important?
It reduces the size of the device
It minimizes the delay between user input and spoken output
It increases battery consumption
It improves Wi‑Fi signal strength
Explanation - Low latency ensures the spoken response follows the user’s command quickly, making conversation natural.
Correct answer is: It minimizes the delay between user input and spoken output
Q.27 What does the term ‘degrees of freedom (DoF)’ describe in a robotic prosthetic arm?
The number of battery cells
The number of independent joint movements
The speed of the motor
The weight of the device
Explanation - DoF refers to how many separate motions (e.g., shoulder rotation, elbow flexion) the prosthesis can perform.
Correct answer is: The number of independent joint movements
Q.28 Which communication aid uses a matrix of lights that flash in patterns to convey messages to a user with visual impairment?
Braille display
LED sign language board
Morse code torch
Vibration pad
Explanation - Morse code torches emit short and long flashes representing dots and dashes, allowing communication via light patterns.
Correct answer is: Morse code torch
Q.29 In a powered wheelchair, a ‘tilt‑in‑space’ function primarily helps with:
Increasing top speed
Reducing battery consumption
Pressure relief and postural changes
Improving GPS accuracy
Explanation - Tilt‑in‑space tilts the seat and backrest together, redistributing pressure to prevent sores.
Correct answer is: Pressure relief and postural changes
Q.30 What is the main advantage of using a solid‑state relay (SSR) over an electromechanical relay in assistive devices?
Higher mechanical wear
Faster switching and longer life
Lower voltage handling
Increased audible noise
Explanation - SSRs have no moving parts, allowing rapid switching and higher reliability.
Correct answer is: Faster switching and longer life
Q.31 A user of a wheelchair wants to control the device using facial expressions. Which technology is essential for this application?
Infrared proximity sensor
Electromyography (EMG) electrodes
Computer vision camera with facial recognition
Ultrasonic distance sensor
Explanation - Computer vision can detect and interpret facial gestures to generate control commands.
Correct answer is: Computer vision camera with facial recognition
Q.32 Which of the following is a common method for providing environmental control (e.g., turning lights on/off) for a user with limited hand function?
Voice‑activated smart plugs
Manual wall switches
Mechanical levers
Analog thermostats
Explanation - Voice‑controlled smart plugs let users operate appliances without needing hand interaction.
Correct answer is: Voice‑activated smart plugs
Q.33 In the context of assistive communication devices, what does the term “text‑to‑speech (TTS)” refer to?
Converting spoken words into written text
Translating typed text into audible speech
Encrypting messages for privacy
Compressing audio files
Explanation - TTS engines synthesize human‑like voice output from written input, enabling speech for non‑verbal users.
Correct answer is: Translating typed text into audible speech
Q.34 Which parameter is most critical when selecting a wireless link for real‑time control of a powered wheelchair?
Bandwidth
Latency
Signal encryption strength
Color of the antenna
Explanation - Low latency ensures command signals reach the wheelchair promptly, essential for safe operation.
Correct answer is: Latency
Q.35 A prosthetic hand that uses surface EMG (sEMG) sensors detects muscle activity from:
Inside the bone marrow
The skin surface overlying the forearm muscles
The brain's motor cortex
The user’s heart rhythm
Explanation - sEMG electrodes pick up electrical potentials generated by muscle contractions through the skin.
Correct answer is: The skin surface overlying the forearm muscles
Q.36 Which safety standard is specifically aimed at the electrical safety of medical devices, including rehabilitation equipment?
IEC 60601
ISO 9001
IEEE 802.3
ANSI Z136
Explanation - IEC 60601 outlines requirements for basic safety and essential performance of medical electrical equipment.
Correct answer is: IEC 60601
Q.37 In a speech‑generating AAC device, what is the purpose of a ‘word prediction’ algorithm?
To automatically translate speech into another language
To suggest the most likely next word, reducing keystrokes
To increase the volume of the spoken output
To detect background noise
Explanation - Word prediction speeds up text entry, making communication faster for users with limited motor control.
Correct answer is: To suggest the most likely next word, reducing keystrokes
Q.38 Which component in a powered mobility device is responsible for converting the stored chemical energy of the battery into mechanical energy?
Motor controller
Inverter
Electric motor
Battery management system
Explanation - The electric motor transforms electrical energy from the battery into rotational mechanical energy that drives the wheels.
Correct answer is: Electric motor
Q.39 A user with limited hand dexterity wants to control a tablet computer. Which assistive input device is most appropriate?
Standard mouse
Trackball
Foot‑pedal switch
Gaming joystick
Explanation - A foot‑pedal provides an alternative input method using the foot, freeing the hands for other tasks.
Correct answer is: Foot‑pedal switch
Q.40 Which type of battery management system (BMS) feature prevents over‑discharging of a wheelchair’s lithium‑ion battery?
Cell balancing
Thermal runaway detection
Low‑voltage cut‑off
Fast‑charging mode
Explanation - A low‑voltage cut‑off disconnects the load when the battery voltage falls below a safe threshold, protecting battery health.
Correct answer is: Low‑voltage cut‑off
Q.41 What is the main advantage of using a capacitive touch sensor over a mechanical button in a communication aid?
Higher power consumption
No moving parts, resulting in longer lifespan
Reduced sensitivity to user input
Increased size
Explanation - Capacitive sensors detect touch via changes in electrical field, eliminating wear and tear associated with mechanical switches.
Correct answer is: No moving parts, resulting in longer lifespan
Q.42 In a powered exoskeleton for gait assistance, the term ‘assist‑as‑needed’ refers to:
Providing maximum assistance at all times
Adjusting the level of assistance based on the user's effort
Turning off the device after a set time
Using a fixed torque value for every step
Explanation - Assist‑as‑needed systems monitor user input and provide just enough power to augment the natural movement.
Correct answer is: Adjusting the level of assistance based on the user's effort
Q.43 Which sensor would you integrate into a wheelchair to detect a steep incline and automatically reduce speed?
Gyroscope
Temperature sensor
Proximity sensor
Magnetometer
Explanation - A gyroscope measures angular velocity and tilt, enabling detection of steep slopes for speed adjustment.
Correct answer is: Gyroscope
Q.44 For a speech‑generating device, why is a high signal‑to‑noise ratio (SNR) important in the microphone input?
It makes the device heavier
It ensures clear voice capture for accurate processing
It reduces battery life
It limits the range of the device
Explanation - A high SNR means the voice signal is much stronger than background noise, improving speech recognition and synthesis quality.
Correct answer is: It ensures clear voice capture for accurate processing
Q.45 Which communication protocol is commonly used for connecting a Bluetooth AAC (Augmentative and Alternative Communication) device to an Android tablet?
RFCOMM
I2C
SPI
Modbus
Explanation - RFCOMM provides a virtual serial port over Bluetooth, suitable for data exchange between AAC devices and tablets.
Correct answer is: RFCOMM
Q.46 In the context of a powered wheelchair, the term ‘range anxiety’ refers to:
Fear of falling over
Concern about battery depletion before reaching a destination
Worry about the device’s speed
Anxiety about operating the joystick
Explanation - Range anxiety is common among electric vehicle users, including wheelchair users, when battery life may not meet travel needs.
Correct answer is: Concern about battery depletion before reaching a destination
Q.47 A wearable assistive device that provides haptic cues for navigation typically uses which type of actuator?
Piezoelectric buzzer
Linear resonant actuator (LRA)
DC motor with gearhead
Solenoid valve
Explanation - LRAs produce precise, controllable vibrations ideal for tactile feedback in navigation aids.
Correct answer is: Linear resonant actuator (LRA)
Q.48 Which of the following best describes the purpose of a ‘fail‑safe’ mode in an assistive mobility device?
To increase maximum speed
To shut down the device immediately in case of a fault
To enable Bluetooth connectivity
To reduce the device’s weight
Explanation - Fail‑safe mechanisms prevent unsafe operation by stopping the device when a critical error is detected.
Correct answer is: To shut down the device immediately in case of a fault
Q.49 In a wheelchair’s electronic control unit (ECU), what is the primary function of the PWM (Pulse Width Modulation) signal?
To encode digital data for Wi‑Fi
To control motor speed by varying duty cycle
To measure battery temperature
To provide GPS coordinates
Explanation - PWM adjusts the average voltage applied to the motor, allowing fine speed control.
Correct answer is: To control motor speed by varying duty cycle
Q.50 Which component in a prosthetic hand is responsible for converting electrical signals into mechanical motion of the fingers?
Microcontroller
Battery pack
Servo motor
RFID tag
Explanation - Servo motors provide precise angular movement, enabling finger flexion and extension based on control signals.
Correct answer is: Servo motor
Q.51 A user with severe quadriplegia wants to control a powered wheelchair using brain signals. Which technology would be most appropriate?
EEG‑based brain‑computer interface (BCI)
Infrared eye tracker
Voice command system
Sip‑and‑puff switch
Explanation - EEG measures brain electrical activity, which can be decoded into control commands for a wheelchair.
Correct answer is: EEG‑based brain‑computer interface (BCI)
Q.52 In a communication aid that uses a 6×6 Braille display, how many dots can be shown simultaneously?
12
36
72
6
Explanation - A 6×6 matrix contains 36 individual Braille dots that can be raised or lowered.
Correct answer is: 36
Q.53 Which of the following is a typical method for providing power redundancy in a critical assistive device?
Using two identical batteries in parallel
Increasing the voltage of a single battery
Adding a larger speaker
Installing a solar panel only
Explanation - Parallel batteries share load and provide backup if one fails, ensuring continuous operation.
Correct answer is: Using two identical batteries in parallel
Q.54 A powered wheelchair equipped with a ‘hill‑climb mode’ primarily changes which parameter?
Wheel size
Motor torque and gear ratio
Battery voltage
Seat height
Explanation - Hill‑climb mode engages a lower gear or increases torque to overcome steep inclines.
Correct answer is: Motor torque and gear ratio
Q.55 Which standard defines the wireless frequency band used by most Bluetooth devices, including many AAC aids?
IEEE 802.11ac
IEEE 802.15.1
ISO 9001
IEC 61000
Explanation - IEEE 802.15.1 is the formal name for Bluetooth, operating in the 2.4 GHz ISM band.
Correct answer is: IEEE 802.15.1
Q.56 What is the purpose of ‘cell balancing’ in a multi‑cell lithium‑ion battery pack used for mobility aids?
To ensure each cell charges and discharges at the same rate
To increase the temperature of the pack
To reduce the overall capacity
To change the cell chemistry
Explanation - Cell balancing equalizes voltage among cells, preventing over‑charge or deep‑discharge of individual cells.
Correct answer is: To ensure each cell charges and discharges at the same rate
Q.57 A wheelchair’s joystick can be configured for left‑handed users. This is an example of:
Ergonomic customization
Battery management
Wireless encryption
Signal amplification
Explanation - Changing control orientation to suit user preference improves comfort and usability.
Correct answer is: Ergonomic customization
Q.58 Which technology enables a user to control a powered wheelchair using head movements without physical contact?
Infrared proximity sensor
Magnetometer‑based compass
Inertial measurement unit (IMU)
Capacitive touch sensor
Explanation - An IMU combines accelerometers and gyroscopes to detect head orientation and translate it into control commands.
Correct answer is: Inertial measurement unit (IMU)
Q.59 In an AAC device, which file format is most commonly used for storing pre‑recorded voice prompts?
MP3
WAV
AVI
PDF
Explanation - WAV files are uncompressed, ensuring high audio quality for clear speech output.
Correct answer is: WAV
Q.60 What is the main benefit of using a brushless DC (BLDC) motor in a powered wheelchair?
Higher maintenance due to brushes
Reduced electrical noise and higher efficiency
Increased size and weight
Simpler control circuitry
Explanation - BLDC motors lack brushes, resulting in smoother operation, less maintenance, and better efficiency.
Correct answer is: Reduced electrical noise and higher efficiency
Q.61 Which method is commonly employed to prevent accidental activation of a sip‑and‑puff switch?
Requiring a minimum pressure threshold
Using a loud alarm
Connecting it to a high‑voltage source
Placing it in a water‑proof housing
Explanation - A pressure threshold distinguishes intentional sips/puffs from accidental breaths.
Correct answer is: Requiring a minimum pressure threshold
Q.62 In a robotic exoskeleton, which sensor provides information about the user’s intention to lift a foot?
Force‑sensing resistor (FSR)
Gyroscope
Electroencephalogram (EEG)
Infrared distance sensor
Explanation - FSRs placed under the foot detect weight shift, indicating the user’s intent to step.
Correct answer is: Force‑sensing resistor (FSR)
Q.63 What does the term ‘latency’ refer to in a wireless AAC communication system?
The time taken to charge the device
The delay between user input and auditory output
The number of Bluetooth devices paired
The size of the device’s storage
Explanation - Low latency is crucial for natural conversation flow in speech‑generating devices.
Correct answer is: The delay between user input and auditory output
Q.64 A wheelchair equipped with an ‘anti‑tip’ sensor will most likely trigger:
An audible alarm only
Automatic braking or speed reduction
Increase in seat height
Activation of headlights
Explanation - The system intervenes to prevent loss of stability when a tipping condition is detected.
Correct answer is: Automatic braking or speed reduction
Q.65 Which communication protocol is best suited for high‑speed data transfer between a prosthetic hand’s processor and its tactile sensors?
I²C
CAN
UART
SPI
Explanation - SPI offers higher data rates than I²C or UART, making it suitable for real‑time tactile feedback.
Correct answer is: SPI
Q.66 In a wheelchair’s control software, a ‘watchdog timer’ is used to:
Monitor battery temperature
Detect software hangs and reset the system if necessary
Control the speed of the vehicle
Adjust seat recline angle
Explanation - A watchdog timer ensures the system recovers from unexpected failures, maintaining safety.
Correct answer is: Detect software hangs and reset the system if necessary
Q.67 A user with limited speech wants to use a picture‑based AAC device. Which display technology is most common for showing the pictures?
E‑ink
LCD touchscreen
LED matrix
CRT monitor
Explanation - LCD touchscreens provide clear, colorful images with responsive touch input, ideal for picture‑based communication.
Correct answer is: LCD touchscreen
Q.68 Which type of motor is typically used for the steering mechanism in a powered wheelchair?
Stepper motor
Servo motor
Brushless DC motor
Linear actuator
Explanation - Servo motors provide precise angular control necessary for accurate steering adjustments.
Correct answer is: Servo motor
Q.69 In a prosthetic limb, what is the purpose of a ‘socket’?
To house the battery pack
To connect the prosthetic to the residual limb securely
To store spare parts
To provide wireless connectivity
Explanation - The socket custom‑fits the user’s stump, distributing loads and enabling control of the prosthetic.
Correct answer is: To connect the prosthetic to the residual limb securely
Q.70 Which wireless technology offers the longest range for remote control of a mobility aid (up to several hundred meters)?
Wi‑Fi
Bluetooth Classic
Zigbee
LoRaWAN
Explanation - LoRaWAN provides low‑power, long‑range communication, suitable for remote monitoring of mobility devices.
Correct answer is: LoRaWAN
Q.71 A wheelchair’s ‘speed limiter’ is primarily designed to:
Prevent the user from exceeding safe velocities
Increase battery life by limiting acceleration
Enable faster climbing of steep hills
Reduce noise emissions
Explanation - Speed limiters ensure the wheelchair operates within legal and safety speed limits.
Correct answer is: Prevent the user from exceeding safe velocities
Q.72 Which of the following best describes a ‘soft‑start’ feature in a powered wheelchair’s motor controller?
Instantly reaching maximum speed
Gradually ramping up motor voltage to avoid sudden jerks
Turning off the battery when idle
Switching between AC and DC power
Explanation - Soft‑start smooths acceleration, enhancing user comfort and reducing mechanical stress.
Correct answer is: Gradually ramping up motor voltage to avoid sudden jerks
Q.73 In an eye‑tracking AAC system, the term ‘gaze dwell time’ refers to:
The speed of eye movement
The length of time the user looks at a target before it is selected
The calibration interval
The battery life of the device
Explanation - Dwell time determines how long a user must focus on an item for the system to register a command.
Correct answer is: The length of time the user looks at a target before it is selected
Q.74 Which safety feature should be present in a powered wheelchair to protect users from electric shock?
Ground fault circuit interrupter (GFCI)
High‑gain antenna
Loudspeaker
Colorful paint
Explanation - GFCI detects leakage currents and quickly disconnects power, preventing shock.
Correct answer is: Ground fault circuit interrupter (GFCI)
Q.75 A speech‑generating AAC device uses a ‘concatenative synthesis’ method. This means:
It generates speech by stitching together small prerecorded sound units
It uses a single continuous tone for all words
It records the user’s own voice for playback
It synthesizes speech using a neural network
Explanation - Concatenative synthesis assembles phonemes or diphones from a database to form words.
Correct answer is: It generates speech by stitching together small prerecorded sound units
Q.76 In a prosthetic knee joint, a ‘microprocessor‑controlled hydraulic damper’ primarily serves to:
Increase battery voltage
Regulate the speed of knee flexion and extension for smoother gait
Charge the prosthetic’s battery
Emit auditory feedback
Explanation - The damper adjusts resistance based on walking phase, providing a natural feel.
Correct answer is: Regulate the speed of knee flexion and extension for smoother gait
Q.77 Which of the following is an advantage of using a modular battery pack design in a powered wheelchair?
Reduced overall weight
Easier replacement of individual cells
Higher voltage output
Simpler wiring
Explanation - Modular packs allow faulty cells to be swapped without discarding the entire battery.
Correct answer is: Easier replacement of individual cells
Q.78 A communication aid that uses a 4×4 matrix keypad for input is primarily designed for:
High‑speed typing
Users with limited fine motor control
Gaming applications
Audio playback
Explanation - A reduced‑size keypad minimizes the precision needed for each press.
Correct answer is: Users with limited fine motor control
Q.79 Which algorithm is commonly employed for smoothing noisy EMG signals in a prosthetic controller?
Fast Fourier Transform (FFT)
Moving average filter
Binary search
Dijkstra’s algorithm
Explanation - A moving average reduces high‑frequency noise, providing a cleaner EMG signal for control.
Correct answer is: Moving average filter
Q.80 In an assistive mobility device, the term ‘torque ripple’ refers to:
Fluctuations in motor torque output during operation
The device’s color variation
Battery temperature changes
Wireless signal strength
Explanation - Torque ripple can cause vibration and uneven motion, so designers aim to minimize it.
Correct answer is: Fluctuations in motor torque output during operation
Q.81 Which of the following sensors would be most effective for detecting a user’s foot pressure in a standing assist device?
Piezoelectric pressure sensor
Hall‑effect sensor
Thermistor
Optical encoder
Explanation - Piezoelectric sensors generate voltage proportional to applied pressure, suitable for foot‑load detection.
Correct answer is: Piezoelectric pressure sensor
Q.82 What is the main function of a ‘diagnostic LED’ on a powered wheelchair’s control panel?
To indicate battery level
To display error codes or status messages
To control motor speed
To provide GPS coordinates
Explanation - Diagnostic LEDs blink in patterns that correspond to specific fault conditions.
Correct answer is: To display error codes or status messages
Q.83 A user with severe tremors may benefit most from which type of joystick modification?
A larger joystick with built‑in low‑pass filter
A joystick with higher sensitivity
A joystick with a metal casing
A joystick with a detachable cable
Explanation - A low‑pass filter smooths out rapid, unintended movements caused by tremors.
Correct answer is: A larger joystick with built‑in low‑pass filter
Q.84 Which communication protocol is specifically designed for real‑time control of multiple devices in a vehicle, including assistive mobility platforms?
CAN bus
I2C
UART
Modbus
Explanation - CAN bus offers robust, deterministic communication suitable for safety‑critical vehicle systems.
Correct answer is: CAN bus
Q.85 In a wheelchair, a ‘reverse gear’ is implemented in the motor controller by:
Changing the polarity of the voltage applied to the motor
Increasing the battery voltage
Activating the brake pads
Switching to a higher gear ratio
Explanation - Reversing voltage direction causes the motor to spin in the opposite direction, moving the wheelchair backward.
Correct answer is: Changing the polarity of the voltage applied to the motor
Q.86 Which feature in an AAC tablet app helps users with limited reading ability?
Voice output of selected items
High‑contrast dark mode
Customizable keyboard layout
Battery saver mode
Explanation - Auditory feedback reads aloud the chosen symbol, assisting users who cannot read text.
Correct answer is: Voice output of selected items
Q.87 A powered exoskeleton that assists lifting tasks must primarily consider which biomechanical factor?
Hip joint torque
Finger grip strength
Eye‑hand coordination
Neck rotation
Explanation - Lifting involves significant forces at the hips; adequate torque ensures safe assistance.
Correct answer is: Hip joint torque
Q.88 What does the term ‘haptic feedback’ mean in the context of a communication aid?
Visual cues on a screen
Vibration or tactile sensations to confirm user actions
Audio alerts for errors
Temperature changes in the device
Explanation - Haptic feedback provides touch‑based confirmation, useful for users with visual impairments.
Correct answer is: Vibration or tactile sensations to confirm user actions
Q.89 Which type of solar cell is most commonly integrated into portable assistive devices for supplemental charging?
Monocrystalline silicon
CdTe thin‑film
Perovskite
Organic polymer
Explanation - Monocrystalline cells offer high efficiency and durability in compact form factors.
Correct answer is: Monocrystalline silicon
Q.90 In a prosthetic limb, the term ‘feed‑forward control’ refers to:
Reacting to sensor data after a movement occurs
Predicting user intent and adjusting actuation before movement
Providing power backup
Measuring temperature of the motor
Explanation - Feed‑forward control anticipates the needed action, improving responsiveness and smoothness.
Correct answer is: Predicting user intent and adjusting actuation before movement
Q.91 A wheelchair equipped with a ‘dynamic seat’ that moves slightly during travel primarily aims to:
Increase speed
Reduce pressure sores by micro‑shifting the user's weight
Charge the battery
Improve steering accuracy
Explanation - Dynamic seating periodically changes pressure distribution, lowering the risk of tissue damage.
Correct answer is: Reduce pressure sores by micro‑shifting the user's weight
Q.92 Which communication interface is typically used for firmware updates in assistive mobility devices?
USB‑C
RS‑232 serial port
HDMI
VGA
Explanation - USB‑C supports high data rates, power delivery, and is widely adopted for device updates.
Correct answer is: USB‑C
Q.93 In a wheelchair’s electronics, ‘EMI shielding’ is employed to:
Reduce electromagnetic interference that could affect device performance
Increase battery capacity
Improve Wi‑Fi signal strength
Make the device waterproof
Explanation - Shielding prevents external electromagnetic fields from disrupting sensitive circuits.
Correct answer is: Reduce electromagnetic interference that could affect device performance
Q.94 A user with limited upper‑body strength uses a ‘head mouse’ to operate a computer. The head mouse detects movement using:
Infrared camera tracking head position
Magnetic field variations
Force‑sensing resistors under the chin
Capacitive touch on the forehead
Explanation - Infrared cameras track the user's head movements and translate them into cursor motion.
Correct answer is: Infrared camera tracking head position
Q.95 Which of the following best describes the function of a ‘load cell’ in an assistive robotic arm?
To measure the force applied by the gripper
To store energy
To provide wireless connectivity
To generate sound
Explanation - Load cells convert mechanical force into an electrical signal, enabling force‑controlled grasping.
Correct answer is: To measure the force applied by the gripper
Q.96 In a speech‑generating device, why is a ‘voice‑bank’ important?
It stores different synthetic voices and languages for personalized output
It provides extra storage for photos
It boosts Wi‑Fi range
It charges the battery
Explanation - A voice‑bank allows the device to produce speech in various tones, accents, and languages.
Correct answer is: It stores different synthetic voices and languages for personalized output
Q.97 Which type of actuator is most appropriate for fine‑grip control in a myoelectric prosthetic hand?
Linear hydraulic actuator
Brushless DC motor with gear reduction
Pneumatic cylinder
Stepper motor without gear reduction
Explanation - Brushless DC motors provide smooth, precise motion, and gear reduction enhances torque for delicate grip tasks.
Correct answer is: Brushless DC motor with gear reduction
Q.98 A wheelchair’s ‘terrain mode’ that automatically adjusts speed and torque based on surface type relies on which sensor combination?
Ultrasonic and temperature sensors
Accelerometer and gyroscope
Wheel slip sensor and inclinometer
Magnetometer and barometer
Explanation - Slip detection and tilt measurement inform the controller about the terrain, allowing adaptive performance.
Correct answer is: Wheel slip sensor and inclinometer
Q.99 What is the main advantage of using a ‘dual‑channel’ EMG acquisition system in a prosthetic controller?
It reduces power consumption
It captures muscle activity from two separate sites for richer intent detection
It eliminates the need for a battery
It provides wireless internet access
Explanation - Dual‑channel EMG enables the system to differentiate between multiple muscle commands, improving control fidelity.
Correct answer is: It captures muscle activity from two separate sites for richer intent detection
Q.100 In a wheelchair’s control architecture, the ‘state machine’ is used to:
Store user passwords
Manage different operational modes (e.g., idle, moving, error)
Adjust LED brightness
Calculate battery capacity
Explanation - A state machine defines distinct system states and transitions, ensuring organized behavior.
Correct answer is: Manage different operational modes (e.g., idle, moving, error)
Q.101 Which of the following is a typical method for a user to select a message on a grid‑based AAC device using a single switch?
Scanning with row‑column activation
Voice command
Eye‑tracking
Gesture control
Explanation - Scanning highlights rows and then columns; the user activates the switch when the desired item is highlighted.
Correct answer is: Scanning with row‑column activation
Q.102 A powered wheelchair’s ‘anti‑collision’ system typically utilizes:
Ultrasonic or LiDAR sensors to detect obstacles
Temperature sensors
Pressure sensors on the seat
Magnetic reed switches
Explanation - These sensors provide distance measurements that enable the system to stop or steer away from obstacles.
Correct answer is: Ultrasonic or LiDAR sensors to detect obstacles
Q.103 Which protocol is most appropriate for connecting multiple sensors (e.g., EMG, force, angle) to a central microcontroller in a prosthetic limb?
SPI
CAN
I²C
UART
Explanation - I²C supports multiple slave devices on two wires, simplifying wiring for many low‑speed sensors.
Correct answer is: I²C
Q.104 In a wheelchair, a ‘soft‑brake’ function is designed to:
Engage the brakes abruptly
Gradually reduce speed to a stop for smoother deceleration
Increase battery voltage
Enable faster hill climbing
Explanation - Soft‑brake avoids sudden stops, improving comfort and safety.
Correct answer is: Gradually reduce speed to a stop for smoother deceleration
Q.105 Which type of display is most energy‑efficient for a portable AAC device that primarily shows static symbols?
LCD with backlight
OLED
E‑ink
LED matrix
Explanation - E‑ink consumes power only when the display changes, making it ideal for static content.
Correct answer is: E‑ink
Q.106 A prosthetic ankle that adapts its stiffness in real time uses which kind of actuator?
Variable‑stiffness spring
Pneumatic cylinder with adjustable pressure
Electroactive polymer
Linear actuator with fixed spring
Explanation - Changing air pressure modulates the effective stiffness of the ankle joint.
Correct answer is: Pneumatic cylinder with adjustable pressure
Q.107 In a wheelchair’s electronic system, the term ‘firmware’ refers to:
The physical hardware components
The low‑level software that directly controls the hardware
The user manual
The battery chemistry
Explanation - Firmware resides in non‑volatile memory and manages hardware functions like motor control.
Correct answer is: The low‑level software that directly controls the hardware
Q.108 Which of the following is a key consideration when designing a wheelchair for outdoor use?
Water‑resistant sealing of electronics
Maximum screen brightness
Number of Bluetooth profiles supported
Availability of a built‑in coffee maker
Explanation - Outdoor environments expose devices to rain and humidity; proper sealing protects against damage.
Correct answer is: Water‑resistant sealing of electronics
Q.109 A user wants to control a powered wheelchair using a handheld joystick that also provides force feedback. Which technology enables this feedback?
Piezoelectric buzzers
Haptic motor with vibration
LED indicator lights
Acoustic speaker
Explanation - Haptic motors create tactile sensations that inform the user about terrain or obstacles.
Correct answer is: Haptic motor with vibration
Q.110 What is the primary purpose of a ‘charge controller’ in a wheelchair’s battery system?
To regulate the voltage and current during charging to protect the battery
To increase the speed of the wheelchair
To provide GPS navigation
To generate sound alerts
Explanation - Charge controllers prevent over‑charging and ensure safe, efficient battery replenishment.
Correct answer is: To regulate the voltage and current during charging to protect the battery
Q.111 In a speech‑generating device, which component converts digital text into an analog audio signal for speaker output?
Digital‑to‑Analog Converter (DAC)
Analog‑to‑Digital Converter (ADC)
Microcontroller
Battery management system
Explanation - The DAC translates digital audio data into voltage variations that drive the speaker.
Correct answer is: Digital‑to‑Analog Converter (DAC)
Q.112 Which design principle is most important for ensuring that a mobility aid can be used by users of various sizes?
Adjustability
Fixed geometry
Heavy materials
Bright color
Explanation - Adjustable components (seat height, armrest width, joystick position) accommodate different body dimensions.
Correct answer is: Adjustability
Q.113 A prosthetic limb that uses a ‘myoelectric’ control system relies on which type of signal?
Electrical potentials generated by muscle activity
Acoustic vibrations
Thermal gradients
Magnetic field variations
Explanation - Myoelectric systems detect EMG signals to infer the user’s intended movement.
Correct answer is: Electrical potentials generated by muscle activity
Q.114 Which wireless technology is most suitable for streaming high‑quality audio from a speech‑generating device to a Bluetooth headset?
Bluetooth Classic (A2DP)
BLE (Bluetooth Low Energy)
Zigbee
Wi‑Fi Direct
Explanation - A2DP supports higher bitrate audio suitable for clear speech playback.
Correct answer is: Bluetooth Classic (A2DP)
Q.115 In a wheelchair, the term ‘range extender’ generally refers to:
A secondary battery pack that increases total travel distance
A device that makes the wheelchair louder
A software update
A decorative accessory
Explanation - Range extenders add extra capacity, allowing longer operation between charges.
Correct answer is: A secondary battery pack that increases total travel distance
Q.116 Which of the following sensor modalities is least likely to be affected by ambient lighting conditions?
Infrared proximity sensor
Visible‑light camera
Photodiode light sensor
Color camera
Explanation - Infrared sensors operate outside the visible spectrum, making them robust against changes in ambient light.
Correct answer is: Infrared proximity sensor
Q.117 A user with limited finger dexterity uses a ‘switch‑controlled scanning’ AAC device. How does the system typically progress through options?
Randomly flashing icons
Sequentially highlighting items at a fixed rate
Voice‑activated selection
Gesture‑based navigation
Explanation - Scanning cycles through choices; the user activates the switch when the desired item is highlighted.
Correct answer is: Sequentially highlighting items at a fixed rate
Q.118 Which component in a prosthetic hand provides the necessary torque for finger flexion?
Microcontroller
Servo motor
Battery pack
Wireless antenna
Explanation - Servo motors can deliver controlled torque to move finger joints accurately.
Correct answer is: Servo motor
Q.119 In an assistive robot for wheelchair users, the term ‘human‑robot interaction (HRI)’ mainly concerns:
The robot’s battery size
The way the user communicates intentions to the robot and receives feedback
The robot’s color scheme
The type of wheels used
Explanation - HRI focuses on intuitive, safe, and effective communication between humans and robots.
Correct answer is: The way the user communicates intentions to the robot and receives feedback
Q.120 Which of the following is a key advantage of using a ‘solid‑state’ battery over a traditional liquid electrolyte battery in a lightweight mobility aid?
Higher risk of leakage
Greater energy density and improved safety
Increased weight
Longer charging time
Explanation - Solid‑state batteries are less prone to leakage and can store more energy per unit mass.
Correct answer is: Greater energy density and improved safety
Q.121 A communication aid that converts typed text into sign‑language video output is primarily aimed at:
Hearing‑impaired users
Visually‑impaired users
Non‑verbal users who want to communicate with signers
Users who prefer audio feedback
Explanation - The device creates visual sign‑language output, allowing communication with people who understand sign language.
Correct answer is: Non‑verbal users who want to communicate with signers
Q.122 Which algorithm is commonly used to convert raw EMG signals into discrete control commands for a prosthetic hand?
Linear discriminant analysis (LDA)
QuickSort
A* pathfinding
SHA‑256 hashing
Explanation - LDA separates EMG patterns into distinct classes corresponding to intended hand motions.
Correct answer is: Linear discriminant analysis (LDA)
Q.123 In a wheelchair’s power system, the term ‘state of charge (SOC)’ indicates:
The remaining capacity of the battery as a percentage of its full charge
The speed of the wheelchair
The temperature of the motor
The GPS location of the device
Explanation - SOC helps users know how much energy is left before recharging is needed.
Correct answer is: The remaining capacity of the battery as a percentage of its full charge
Q.124 A prosthetic device that employs a ‘closed‑loop’ control system uses feedback from:
Only the user’s intention
Sensors such as force or position to adjust actuation in real time
The ambient temperature
A pre‑programmed timer
Explanation - Closed‑loop control continuously monitors output and corrects it, improving accuracy.
Correct answer is: Sensors such as force or position to adjust actuation in real time
Q.125 Which feature helps a wheelchair user maintain orientation in an indoor environment?
Built‑in GPS receiver
Beacon‑based indoor positioning system
Solar panel
High‑capacity battery
Explanation - Beacons (e.g., Bluetooth Low Energy) can provide accurate location data where GPS signals are unavailable.
Correct answer is: Beacon‑based indoor positioning system
Q.126 In a speech‑generating device, the ‘phoneme‑based synthesis’ approach differs from ‘concatenative synthesis’ primarily by:
Using mathematical models to generate speech sounds rather than stitching recorded units
Providing higher battery consumption
Requiring a larger storage space
Only working with pre‑recorded voices
Explanation - Phoneme‑based synthesis creates speech via algorithms, allowing greater flexibility at the cost of naturalness.
Correct answer is: Using mathematical models to generate speech sounds rather than stitching recorded units
Q.127 A wheelchair equipped with a ‘remote‑control’ feature that can be accessed via a smartphone uses which communication technology?
Bluetooth Low Energy (BLE)
Infrared (IR)
Zigbee
NFC
Explanation - BLE provides low‑power, short‑range connectivity suitable for smartphone‑based control.
Correct answer is: Bluetooth Low Energy (BLE)
Q.128 Which of the following is the most common method for calibrating an eye‑tracking AAC system?
Having the user stare at a series of known points on the screen
Measuring ambient light levels
Checking battery voltage
Listening to a tone
Explanation - Calibration maps eye positions to screen coordinates by recording gaze points.
Correct answer is: Having the user stare at a series of known points on the screen
Q.129 In a powered wheelchair, the term ‘regenerative braking’ is most closely associated with:
Converting kinetic energy back into electrical energy during deceleration
Increasing motor speed
Activating the horn
Opening the door
Explanation - Regenerative braking recovers energy that would otherwise be lost as heat, extending battery life.
Correct answer is: Converting kinetic energy back into electrical energy during deceleration
Q.130 Which design consideration is most important for a communication device intended for use in noisy environments?
High‑resolution touchscreen
Noise‑cancelling microphone
Bright LED backlight
Large battery capacity
Explanation - A noise‑cancelling mic improves speech recognition accuracy amidst background noise.
Correct answer is: Noise‑cancelling microphone
Q.131 A wheelchair’s ‘tilt sensor’ primarily measures:
The angle of the seat relative to the ground
Battery temperature
Wheel speed
Signal strength of Wi‑Fi
Explanation - Tilt sensors detect inclination, enabling features like anti‑tip and recline adjustments.
Correct answer is: The angle of the seat relative to the ground
Q.132 What is the primary advantage of using a ‘vector‑control’ algorithm in a wheelchair’s motor driver?
Simplified hardware design
Precise control of motor torque and flux, resulting in smoother operation
Reduced need for batteries
Increased audible noise
Explanation - Vector control (field‑oriented control) separates torque and flux components for efficient motor performance.
Correct answer is: Precise control of motor torque and flux, resulting in smoother operation
Q.133 Which of the following is a typical method for providing haptic feedback in a wearable communication aid?
Vibration motor placed on the forearm
LED flashing on the chest
Audio speaker in the ear
Temperature change on the skin
Explanation - Vibration motors deliver tactile cues that can be felt without visual or auditory reliance.
Correct answer is: Vibration motor placed on the forearm
Q.134 A powered wheelchair's 'hill assist' feature uses which sensor data to automatically adjust motor output?
Inclinometer (tilt) and wheel encoder speed
Ambient light sensor
Microphone input
GPS altitude only
Explanation - Combining tilt angle with wheel speed allows the controller to determine slope and provide appropriate torque.
Correct answer is: Inclinometer (tilt) and wheel encoder speed
Q.135 Which of the following best describes a ‘soft‑switch’ used in assistive technology?
A touch‑sensitive surface that registers a press without moving parts
A mechanical lever with a large travel distance
A voice‑activated command module
A high‑current power relay
Explanation - Soft‑switches use capacitive or resistive sensing, offering durability and low actuation force.
Correct answer is: A touch‑sensitive surface that registers a press without moving parts
Q.136 In a prosthetic hand, a 'grip force sensor' is most commonly implemented using:
Strain gauge
Thermistor
Hall‑effect sensor
Photodiode
Explanation - Strain gauges change resistance with applied force, allowing precise measurement of grip strength.
Correct answer is: Strain gauge
Q.137 What is the primary reason for employing ‘low‑pass filtering’ on EMG signals used in prosthetic control?
To eliminate high‑frequency noise while preserving the muscle activation envelope
To increase the signal amplitude
To convert analog signals to digital
To add latency to the system
Explanation - Low‑pass filters smooth the EMG waveform, making it easier to extract meaningful activation patterns.
Correct answer is: To eliminate high‑frequency noise while preserving the muscle activation envelope
Q.138 A wheelchair equipped with a ‘remote diagnostic’ feature allows technicians to:
Update firmware and read error logs over a wireless connection
Increase the wheelchair’s top speed remotely
Control the wheelchair from another country
Change the seat color remotely
Explanation - Remote diagnostics enable maintenance and troubleshooting without physical access to the device.
Correct answer is: Update firmware and read error logs over a wireless connection
Q.139 Which of the following is a common method for providing visual feedback to a user of a sip‑and‑puff device?
Changing the color of an LED indicator
Emitting a beep sound
Increasing motor torque
Vibrating the seat
Explanation - LED color changes can indicate successful detection of sip or puff inputs.
Correct answer is: Changing the color of an LED indicator
Q.140 In an AAC device that supports multiple languages, the term ‘language pack’ refers to:
A set of firmware files containing vocabulary, grammar rules, and voice data for a specific language
A physical expansion card
A battery extension
A decorative skin
Explanation - Language packs enable the device to produce speech and display symbols in different languages.
Correct answer is: A set of firmware files containing vocabulary, grammar rules, and voice data for a specific language
Q.141 A powered wheelchair’s ‘dynamic suspension’ system primarily improves:
Battery life
Ride comfort over uneven terrain
Maximum speed
Bluetooth connectivity
Explanation - Dynamic suspension adapts to surface irregularities, reducing shocks transmitted to the user.
Correct answer is: Ride comfort over uneven terrain
Q.142 Which sensor type is most suitable for detecting whether a wheelchair user is seated correctly?
Pressure mat under the seat
Proximity sensor on the floor
Accelerometer on the wheels
Ambient light sensor
Explanation - A pressure mat senses weight distribution, confirming proper seating posture.
Correct answer is: Pressure mat under the seat
Q.143 In a prosthetic knee with microprocessor control, the algorithm that predicts gait phase is commonly called:
Finite State Machine (FSM)
Neural Network
Kalman filter
Binary search tree
Explanation - FSMs model the sequential phases of walking (stance, swing) and transition based on sensor inputs.
Correct answer is: Finite State Machine (FSM)
Q.144 Which communication protocol is preferred for high‑reliability, low‑latency data exchange between a prosthetic hand’s controller and its sensors?
CAN bus
Wi‑Fi
Bluetooth Classic
Ethernet
Explanation - CAN bus provides deterministic timing and error handling suitable for safety‑critical prosthetic control.
Correct answer is: CAN bus
Q.145 A wheelchair’s ‘seat tilt’ feature is primarily used for:
Increasing battery capacity
Improving user comfort and pressure redistribution
Enhancing GPS accuracy
Boosting motor power
Explanation - Tilting the seat changes pressure points, helping to prevent sores and increase comfort.
Correct answer is: Improving user comfort and pressure redistribution
Q.146 Which of the following is a typical method for reducing electromagnetic interference (EMI) in a prosthetic device’s wiring?
Using twisted‑pair cables with shielding
Increasing wire length
Using unshielded copper wire
Placing the wires near high‑current motor leads
Explanation - Twisted, shielded cables cancel out magnetic fields and protect against external EMI.
Correct answer is: Using twisted‑pair cables with shielding
Q.147 In an eye‑tracking AAC system, a ‘dwell time’ of 800 ms means:
The system updates the display every 800 ms
The user must stare at an item for 800 ms before it is selected
The device recharges its battery in 800 ms
The camera refresh rate is 800 Hz
Explanation - Dwell time defines the required gaze duration for activation.
Correct answer is: The user must stare at an item for 800 ms before it is selected
Q.148 Which of the following is an advantage of using a ‘modular battery pack’ design in a powered mobility device?
Simplifies field repairs by allowing individual cell replacement
Increases overall weight
Reduces overall voltage
Eliminates need for a charger
Explanation - Modular packs enable swapping faulty cells without discarding the entire battery system.
Correct answer is: Simplifies field repairs by allowing individual cell replacement
Q.149 A communication device that uses a ‘grid‑based scanning’ method requires the user to:
Press a switch when the desired row and column are highlighted
Speak a command aloud
Move the device physically
Shake the device
Explanation - Grid scanning sequentially highlights rows then columns; the user selects via a switch.
Correct answer is: Press a switch when the desired row and column are highlighted
Q.150 Which type of motor controller is typically used to achieve smooth variable speed control in electric wheelchairs?
Pulse‑Width Modulation (PWM) controller
On‑off switch
Mechanical gearbox
Fixed‑ratio transformer
Explanation - PWM varies the duty cycle of voltage to the motor, allowing fine speed adjustments.
Correct answer is: Pulse‑Width Modulation (PWM) controller
Q.151 In a prosthetic arm, the term ‘haptic glove’ usually refers to:
A glove that provides tactile feedback to the user about grip force
A glove that powers the prosthesis
A decorative accessory
A glove that generates electrical signals
Explanation - Haptic gloves convey force information, helping the user sense how tightly they are gripping.
Correct answer is: A glove that provides tactile feedback to the user about grip force