Q.1 What is the primary function of a strain gauge sensor in biomedical instrumentation?
To measure blood pressure
To detect heartbeats
To measure mechanical deformation of a material
To capture electrical activity of the heart
Explanation - Strain gauges detect changes in resistance caused by deformation, making them suitable for measuring force or strain in biomedical devices such as implantable sensors.
Correct answer is: To measure mechanical deformation of a material
Q.2 Which of the following sensors uses light to measure blood oxygen saturation?
Pressure transducer
Accelerometer
Photoplethysmograph (PPG)
Thermistor
Explanation - PPG sensors emit light and detect the amount reflected or transmitted to determine blood oxygen levels (SpO₂).
Correct answer is: Photoplethysmograph (PPG)
Q.3 An electrochemical biosensor typically consists of which three main components?
An electrode, a transducer, and a processor
A sensing element, a signal conditioner, and a display
An electrode, a biorecognition element, and a signal transducer
A sensor, a power supply, and a communication module
Explanation - Electrochemical biosensors combine a biorecognition element (enzyme, antibody) with an electrode that transduces the biochemical interaction into an electrical signal.
Correct answer is: An electrode, a biorecognition element, and a signal transducer
Q.4 Which type of sensor is most appropriate for detecting temperature changes in human tissue?
Piezoelectric sensor
Capacitive pressure sensor
Thermistor
Optical fiber sensor
Explanation - Thermistors change resistance with temperature and are widely used for accurate temperature sensing in medical devices.
Correct answer is: Thermistor
Q.5 What principle does an inductive proximity sensor rely on?
Change in capacitance
Change in inductance
Change in resistance
Change in optical reflection
Explanation - Inductive sensors detect metallic objects by changes in the inductance of a coil when a metal approaches.
Correct answer is: Change in inductance
Q.6 A piezoelectric sensor used in a pulse oximeter generates a signal primarily due to:
Capacitive changes in the tissue
Electrochemical reactions
Mechanical stress from arterial pulsation
Thermal expansion
Explanation - Piezoelectric materials produce charge under mechanical stress; in pulse oximeters, this stress comes from arterial blood flow.
Correct answer is: Mechanical stress from arterial pulsation
Q.7 Which sensor type is best suited for measuring the force applied by a patient on a rehabilitation robot?
Capacitive force sensor
Strain gauge load cell
Photodiode array
Accelerometer
Explanation - Load cells with strain gauges convert mechanical force into a precise electrical signal, ideal for robotic assistance applications.
Correct answer is: Strain gauge load cell
Q.8 In an ECG system, the electrode that measures electrical potentials is known as a:
Capacitive sensor
Temperature sensor
Electrical biosensor
Piezoelectric sensor
Explanation - ECG electrodes are conductive pads that act as electrical biosensors, capturing the heart’s bioelectric activity.
Correct answer is: Electrical biosensor
Q.9 Which type of transducer converts optical signals into electrical signals in a fiber optic sensor?
Photodiode
Photomultiplier tube
Thermopile
Microphone
Explanation - Photodiodes generate current proportional to incident light intensity, making them common in optical fiber biosensors.
Correct answer is: Photodiode
Q.10 A wearable respiration monitor uses which transducer to measure breathing?
Thermistor
Strain gauge
Piezoelectric film
Capacitive humidity sensor
Explanation - Piezoelectric films detect mechanical deformation caused by chest expansion, generating voltage proportional to respiration rate.
Correct answer is: Piezoelectric film
Q.11 What is the main advantage of using an optical fiber sensor for intracranial pressure monitoring?
High electrical conductivity
Immunity to electromagnetic interference
Low cost
Fast response time
Explanation - Optical fibers carry light signals, making them immune to EMI, which is critical in sensitive brain monitoring.
Correct answer is: Immunity to electromagnetic interference
Q.12 Which sensor technology is commonly used in glucose meters for diabetes management?
Electrochemical amperometric sensor
Thermal conductivity sensor
Piezoelectric sensor
Capacitive humidity sensor
Explanation - Glucose meters measure glucose concentration via an electrochemical reaction producing a current proportional to glucose levels.
Correct answer is: Electrochemical amperometric sensor
Q.13 What is the primary role of a signal conditioning circuit in biomedical instrumentation?
To power the sensor
To amplify and filter the sensor output
To store data
To display results on a screen
Explanation - Signal conditioning improves the sensor signal quality before digitization by amplifying, filtering, and offsetting as needed.
Correct answer is: To amplify and filter the sensor output
Q.14 A capacitive humidity sensor works by detecting changes in:
Resonant frequency
Capacitance between plates
Voltage drop across a resistor
Optical absorption
Explanation - Humidity changes the dielectric constant between sensor plates, altering capacitance.
Correct answer is: Capacitance between plates
Q.15 Which type of sensor is typically used to measure intracranial pressure via a catheter?
Fiber Bragg grating sensor
Pressure transducer with fluid-filled catheter
Photoplethysmograph
Temperature sensor
Explanation - A pressure transducer inside the catheter measures hydrostatic pressure changes directly.
Correct answer is: Pressure transducer with fluid-filled catheter
Q.16 Which of the following is NOT a typical noise source in biomedical sensor signals?
Electromyography (EMG) interference
Ambient light in optical sensors
Motion artifacts
Thermal drift
Explanation - EMG is a physiological signal, not a noise source; the other options are common noise contributors.
Correct answer is: Electromyography (EMG) interference
Q.17 What does the term 'biorecognition element' refer to in a biosensor?
The electronic readout circuit
The component that specifically interacts with the target analyte
The power source
The display interface
Explanation - Biorecognition elements (antibodies, enzymes, nucleic acids) provide selective binding to the target molecule.
Correct answer is: The component that specifically interacts with the target analyte
Q.18 Which sensor type would you use to detect changes in body posture in a smart bed?
Accelerometer
Strain gauge pressure sensor
Optical camera
Temperature sensor
Explanation - Pressure sensors map the weight distribution and detect shifts in body position.
Correct answer is: Strain gauge pressure sensor
Q.19 A MEMS accelerometer used in a fall detection wearable typically has which sensitivity range?
±0.5g
±2g
±5g
±10g
Explanation - Most MEMS accelerometers for human motion are designed to capture up to ±2g to detect falls without saturating.
Correct answer is: ±2g
Q.20 Which transducer converts a pressure difference into a measurable electrical voltage?
Strain gauge transducer
Capacitive transducer
Piezoelectric transducer
Optical transducer
Explanation - Piezoelectric materials generate charge when subjected to mechanical pressure, producing a voltage output.
Correct answer is: Piezoelectric transducer
Q.21 What is the key advantage of using a fiber optic strain sensor in a surgical robot?
High bandwidth
Electrical isolation
Low cost
High temperature tolerance
Explanation - Fiber optic sensors are immune to EMI, providing accurate measurements in electrically noisy operating rooms.
Correct answer is: Electrical isolation
Q.22 Which of these sensors would best measure the concentration of CO₂ in exhaled breath?
Thermistor
Metal-oxide sensor
Electrochemical sensor
Strain gauge
Explanation - Metal-oxide sensors respond to gas concentration changes and are commonly used for CO₂ monitoring.
Correct answer is: Metal-oxide sensor
Q.23 A sensor that measures the electrical potential difference across the skin is known as a:
Bioimpedance sensor
Bioelectrical sensor
Biopotential sensor
Biotransistor
Explanation - Biopotential sensors detect small voltage changes, such as those from skin surface potentials.
Correct answer is: Biopotential sensor
Q.24 The primary measurement principle behind a galvanic skin response (GSR) sensor is:
Change in skin temperature
Change in skin conductivity
Change in blood flow
Change in skin thickness
Explanation - GSR sensors monitor sweat-induced changes in skin conductance to assess emotional arousal.
Correct answer is: Change in skin conductivity
Q.25 In a photoplethysmography (PPG) sensor, what wavelength of light is most commonly used?
UV
Visible red
Near-infrared
X-ray
Explanation - Near-infrared light penetrates skin and is absorbed by hemoglobin, allowing pulse measurement.
Correct answer is: Near-infrared
Q.26 Which of the following best describes the purpose of a differential amplifier in a biomedical sensor chain?
To increase sensor sensitivity by multiplying the signal
To subtract the common-mode noise from the signal
To convert analog signals to digital
To power the sensor
Explanation - Differential amplifiers amplify the difference between two inputs while rejecting common-mode signals like noise.
Correct answer is: To subtract the common-mode noise from the signal
Q.27 A blood pressure cuff sensor typically uses which type of transducer?
Piezoelectric strain gauge
Capacitive pressure transducer
Optical sensor
Thermistor
Explanation - Capacitive sensors measure small pressure variations in the cuff, translating them to voltage changes.
Correct answer is: Capacitive pressure transducer
Q.28 What is the typical bandwidth required for an ECG signal?
0.05–100 Hz
1–1000 Hz
10–200 Hz
0.5–150 Hz
Explanation - The main ECG components fall within 0.5–150 Hz, covering the QRS complex and low-frequency baseline.
Correct answer is: 0.5–150 Hz
Q.29 Which sensor would you use to monitor the temperature inside a chemical reactor in a biomedical application?
Thermistor
Thermocouple
Infrared sensor
Biosensor
Explanation - Thermocouples provide accurate temperature readings in high-temperature chemical processes.
Correct answer is: Thermocouple
Q.30 What is the main function of a zero-offset calibration in a biomedical sensor?
To maximize sensor output range
To eliminate sensor drift
To adjust sensor sensitivity
To align sensor frequency response
Explanation - Zero-offset calibration ensures that a sensor’s baseline reading is zero when no stimulus is present.
Correct answer is: To eliminate sensor drift
Q.31 A fiber Bragg grating (FBG) sensor is primarily used for measuring:
Temperature
Strain
Pressure
Light intensity
Explanation - FBG sensors reflect a specific wavelength that shifts with strain or temperature changes, but strain measurement is common in biomedical implants.
Correct answer is: Strain
Q.32 Which sensor type is most suitable for detecting a patient’s tremor in a Parkinson's disease monitoring device?
Accelerometer
Strain gauge
Pressure sensor
Photodiode
Explanation - Accelerometers measure low-frequency motion, ideal for quantifying tremor amplitude and frequency.
Correct answer is: Accelerometer
Q.33 What is the key advantage of using a Hall-effect sensor for position measurement in a medical linear actuator?
High accuracy
Low power consumption
Magnetic shielding
Immunity to EMI
Explanation - Hall-effect sensors rely on magnetic fields and are not affected by electrical noise, ensuring reliable positioning.
Correct answer is: Immunity to EMI
Q.34 Which sensor technology would be used to monitor the oxygen concentration in a hypoxia alarm system?
Optical absorption sensor
Thermistor
Capacitive humidity sensor
Accelerometer
Explanation - Optical absorption sensors detect changes in light intensity caused by varying O₂ concentration.
Correct answer is: Optical absorption sensor
Q.35 Which of the following is NOT a characteristic of a piezoelectric transducer?
Generates voltage when mechanically stressed
Requires external power source
Can sense pressure
Has a linear response to force
Explanation - Piezoelectric transducers generate charge from mechanical stress, requiring no external power.
Correct answer is: Requires external power source
Q.36 A capacitive humidity sensor in a wearable device primarily measures changes in:
Capacitance between two plates
Temperature
Light intensity
Mechanical strain
Explanation - Humidity affects the dielectric constant between sensor plates, altering capacitance.
Correct answer is: Capacitance between two plates
Q.37 Which type of sensor would be ideal for measuring the pressure of a blood vessel in a catheter-based system?
Piezoelectric transducer
Thermistor
Capacitive pressure sensor
Accelerometer
Explanation - Capacitive sensors can be miniaturized for intravascular pressure monitoring with high sensitivity.
Correct answer is: Capacitive pressure sensor
Q.38 Which sensor is commonly used in a pacemaker to detect heart rate?
ECG electrode
Temperature sensor
Accelerometer
Pressure transducer
Explanation - Pacemakers use ECG electrodes to monitor cardiac electrical activity for pacing decisions.
Correct answer is: ECG electrode
Q.39 The sensitivity of a strain gauge sensor is typically expressed in:
Ohms per volt
Microstrain per volt
Volts per meter
Strain per ohm
Explanation - Strain gauge sensitivity indicates how much strain is needed to produce a measurable voltage output.
Correct answer is: Microstrain per volt
Q.40 Which component in a bioelectric sensor ensures that only the target signal is amplified and not the noise?
Band-pass filter
High-pass filter
Differential amplifier
Low-pass filter
Explanation - Differential amplifiers amplify the signal difference while rejecting common-mode noise.
Correct answer is: Differential amplifier
Q.41 What is the typical temperature range for a thermistor used in a fever monitoring patch?
0–20 °C
35–40 °C
20–30 °C
45–55 °C
Explanation - Human body temperature ranges from about 35–40 °C, so thermistors are designed for this range.
Correct answer is: 35–40 °C
Q.42 Which sensor would be most suitable for measuring the concentration of glucose in a continuous glucose monitor?
Optical fiber sensor
Electrochemical sensor
Capacitive sensor
Thermocouple
Explanation - Continuous glucose monitors rely on enzymatic electrochemical reactions to convert glucose levels into measurable current.
Correct answer is: Electrochemical sensor
Q.43 A sensor that changes its resistance in response to pressure is called a:
Thermistor
Piezoelectric sensor
Strain gauge pressure sensor
Photodetector
Explanation - Strain gauge pressure sensors convert pressure-induced strain into resistance changes.
Correct answer is: Strain gauge pressure sensor
Q.44 Which of these sensors is typically used in a non-contact heart rate monitor?
Photoplethysmograph (PPG)
Accelerometer
Strain gauge
Capacitive pressure sensor
Explanation - PPG sensors use light to detect blood volume changes without skin contact.
Correct answer is: Photoplethysmograph (PPG)
Q.45 What is the primary output of an optical fiber strain sensor?
Voltage
Frequency shift
Temperature change
Light intensity
Explanation - Fiber Bragg grating sensors produce a wavelength shift that is converted to strain measurement.
Correct answer is: Frequency shift
Q.46 Which sensor type would best detect the presence of a liquid inside a catheter for a drug delivery system?
Capacitive sensor
Thermocouple
Accelerometer
Piezoelectric transducer
Explanation - Capacitive sensors can detect changes in dielectric constant when liquid enters the catheter.
Correct answer is: Capacitive sensor
Q.47 Which of the following is a key advantage of using a MEMS-based accelerometer in a wearable health monitor?
High power consumption
Large size
Low cost and high integration
Limited sensitivity
Explanation - MEMS accelerometers are miniaturized, low-power, and cost-effective for consumer wearables.
Correct answer is: Low cost and high integration
Q.48 A biosensor that uses a DNA strand to detect a specific pathogen relies on which type of biorecognition?
Enzyme-substrate
Antibody-antigen
DNA hybridization
Nerve signal
Explanation - DNA-based biosensors detect target sequences through complementary base pairing (hybridization).
Correct answer is: DNA hybridization
Q.49 Which of these transducers is best for measuring minute pressure changes in a microfluidic chip?
Piezoelectric crystal
Capacitive pressure sensor
Thermocouple
Photodiode
Explanation - Capacitive pressure sensors can be fabricated on chips to detect small pressure variations.
Correct answer is: Capacitive pressure sensor
Q.50 Which signal conditioning component is used to remove DC offset from a biomedical sensor output?
High-pass filter
Low-pass filter
Band-pass filter
Differential amplifier
Explanation - A high-pass filter blocks DC components, preserving AC signals like ECG while removing offset.
Correct answer is: High-pass filter
Q.51 The primary function of a temperature sensor in a hypothermia treatment device is to monitor:
Heart rate
Skin temperature
Blood pressure
Respiration rate
Explanation - Accurate skin temperature monitoring ensures therapeutic hypothermia is maintained safely.
Correct answer is: Skin temperature
Q.52 Which sensor type is typically used to detect the presence of a metallic implant in medical imaging?
Inductive proximity sensor
Capacitive sensor
Thermal sensor
Optical sensor
Explanation - Inductive sensors detect metallic objects via changes in magnetic fields, useful for implant detection.
Correct answer is: Inductive proximity sensor
Q.53 Which of the following best describes the output of a photodetector in a pulse oximeter?
Analog voltage proportional to light intensity
Digital count of photons
Frequency modulation of light
Thermal output
Explanation - Photodetectors convert incoming light into a proportional electrical voltage.
Correct answer is: Analog voltage proportional to light intensity
Q.54 What is the main challenge when using MEMS sensors in a high-frequency ultrasound imaging system?
Low sensitivity to pressure
High power consumption
Limited bandwidth
High cost
Explanation - MEMS sensors often have limited frequency response compared to specialized ultrasound transducers.
Correct answer is: Limited bandwidth
Q.55 Which transducer is best suited for measuring the vibration of a mechanical heart valve?
Accelerometer
Capacitive sensor
Thermistor
Photodiode
Explanation - Accelerometers can capture dynamic vibration signatures of heart valves.
Correct answer is: Accelerometer
Q.56 The term 'sensor fusion' in biomedical devices refers to:
Combining sensor signals to improve accuracy
Using one sensor to replace all others
Separating sensor outputs into individual signals
Cooling sensors during operation
Explanation - Sensor fusion integrates multiple data streams (e.g., accelerometer + gyroscope) for robust measurement.
Correct answer is: Combining sensor signals to improve accuracy
Q.57 Which type of sensor would you use to detect the pH level inside a patient's bloodstream?
pH electrode
Optical pH sensor
Strain gauge
Temperature sensor
Explanation - pH electrodes measure ion activity through an electrochemical reaction, suitable for in vivo pH monitoring.
Correct answer is: pH electrode
Q.58 Which component of a biomedical sensor system is responsible for converting analog signals to digital format?
Amplifier
ADC (Analog-to-Digital Converter)
DAC (Digital-to-Analog Converter)
Power supply
Explanation - An ADC samples the analog voltage and outputs a digital representation for microcontroller processing.
Correct answer is: ADC (Analog-to-Digital Converter)
Q.59 A sensor that measures the voltage difference across a small metal wire due to temperature change is a:
Thermistor
RTD (Resistance Temperature Detector)
Thermocouple
Photodiode
Explanation - RTDs use the linear relationship between resistance and temperature in a metal wire.
Correct answer is: RTD (Resistance Temperature Detector)
Q.60 Which sensor type is commonly used for detecting the presence of oxygen in a hypoxia warning system?
Metal-oxide semiconductor sensor
Thermocouple
Accelerometer
Strain gauge
Explanation - Metal-oxide sensors change resistance with oxygen partial pressure, enabling hypoxia detection.
Correct answer is: Metal-oxide semiconductor sensor
Q.61 What is the main disadvantage of using a thermistor for deep tissue temperature monitoring?
Low sensitivity
High cost
Limited depth penetration
High power consumption
Explanation - Thermistors are surface-based and cannot measure temperature deep within tissue without invasive placement.
Correct answer is: Limited depth penetration
Q.62 Which sensor is most appropriate for measuring blood glucose levels via a minimally invasive method?
Capacitive sensor
Electrochemical sensor
Photodiode
Accelerometer
Explanation - Electrochemical sensors use glucose oxidase to produce a measurable current related to glucose concentration.
Correct answer is: Electrochemical sensor
Q.63 In a wearable breathing monitor, which sensor provides real-time measurement of airflow velocity?
Pressure sensor
Anemometer (hot-wire sensor)
Accelerometer
Thermistor
Explanation - Hot-wire anemometers measure airflow velocity based on convective cooling of a heated wire.
Correct answer is: Anemometer (hot-wire sensor)
Q.64 A sensor that uses a change in dielectric constant to measure moisture is a:
Capacitive humidity sensor
Resistive sensor
Thermal sensor
Photodiode
Explanation - Capacitive sensors detect moisture through changes in capacitance between electrodes.
Correct answer is: Capacitive humidity sensor
Q.65 Which of the following is a typical application of a photoplethysmography sensor?
Blood glucose measurement
Pulse rate monitoring
Temperature sensing
Motion detection
Explanation - PPG sensors detect blood volume changes to determine heart rate and oxygen saturation.
Correct answer is: Pulse rate monitoring
Q.66 The output of an optical fiber pressure sensor is typically:
A change in light wavelength
A voltage change
A temperature change
A frequency shift
Explanation - Fiber Bragg gratings reflect a specific wavelength that shifts with applied pressure.
Correct answer is: A change in light wavelength
Q.67 Which sensor is used in a wearable ECG patch to measure heart activity?
Accelerometer
ECG electrodes
Temperature sensor
Capacitive pressure sensor
Explanation - ECG patches use conductive electrodes to detect cardiac electrical signals.
Correct answer is: ECG electrodes
Q.68 A sensor that measures the force exerted by a patient's hand on a rehabilitation device should be:
Capacitive pressure sensor
Accelerometer
Thermocouple
Strain gauge load cell
Explanation - Load cells are precise force sensors suitable for measuring grip strength.
Correct answer is: Strain gauge load cell
Q.69 What is the primary advantage of using a MEMS-based gyroscope in a fall detection system?
High energy consumption
Large size
Low cost and high accuracy
Low sensitivity
Explanation - MEMS gyros are compact and cost-effective, enabling widespread deployment in wearables.
Correct answer is: Low cost and high accuracy
Q.70 Which sensor type is best for detecting the presence of a metallic foreign object in a patient's body?
Inductive proximity sensor
Capacitive sensor
Optical sensor
Thermistor
Explanation - Inductive sensors detect metals through changes in magnetic field coupling.
Correct answer is: Inductive proximity sensor
Q.71 In a continuous glucose monitoring system, what is the role of the enzyme glucose oxidase?
To generate light
To convert glucose into an electrical signal
To provide structural support
To measure temperature
Explanation - Glucose oxidase catalyzes the oxidation of glucose, producing electrons that generate current.
Correct answer is: To convert glucose into an electrical signal
Q.72 Which transducer is most commonly used to measure intravascular pressure?
Strain gauge load cell
Piezoelectric transducer
Capacitive pressure sensor
Optical fiber sensor
Explanation - Capacitive sensors can be miniaturized and accurately measure fluid pressure inside blood vessels.
Correct answer is: Capacitive pressure sensor
Q.73 Which of the following best describes an accelerometer’s output signal?
Voltage proportional to acceleration
Temperature-dependent resistance
Frequency modulation
Optical intensity
Explanation - Accelerometers generate a voltage proportional to the sensed acceleration.
Correct answer is: Voltage proportional to acceleration
Q.74 What is the primary function of an ADC in a biomedical instrumentation system?
Amplify analog signals
Convert analog signals to digital
Filter noise
Power the sensor
Explanation - An ADC samples analog voltage and produces a digital representation for processing.
Correct answer is: Convert analog signals to digital
Q.75 Which sensor would be used in a non-invasive blood pressure cuff to detect pulse pressure?
Capacitive pressure sensor
Thermistor
Accelerometer
Piezoelectric sensor
Explanation - Capacitive sensors accurately measure the subtle pressure changes in the cuff during cuff inflation.
Correct answer is: Capacitive pressure sensor
Q.76 Which sensor technology is used for detecting light levels in a phototherapy unit?
Photodiode
Thermistor
Accelerometer
Capacitive sensor
Explanation - Photodiodes sense incident light intensity, useful for controlling phototherapy illumination.
Correct answer is: Photodiode
Q.77 The main advantage of using an inductive sensor for implantable devices is:
High power consumption
Large size
Immunity to electromagnetic interference
Low sensitivity
Explanation - Inductive sensors are robust against EMI, a common concern in implantable electronics.
Correct answer is: Immunity to electromagnetic interference
Q.78 What is the typical output of a thermocouple?
Voltage proportional to temperature difference
Current proportional to temperature
Frequency modulation
Voltage proportional to strain
Explanation - Thermocouples generate a voltage based on the temperature gradient between two junctions.
Correct answer is: Voltage proportional to temperature difference
Q.79 Which sensor would you choose for measuring the concentration of oxygen in a breathing mask?
Electrochemical sensor
Capacitive pressure sensor
Optical absorption sensor
Accelerometer
Explanation - Optical absorption sensors measure O₂ levels based on light absorption characteristics.
Correct answer is: Optical absorption sensor
Q.80 In a medical device, which component provides isolation between the patient and the electronics?
Capacitor
Transformer
Optocoupler
Resistor
Explanation - Optocouplers allow electrical signals to pass while maintaining electrical isolation for patient safety.
Correct answer is: Optocoupler
Q.81 A sensor that uses a change in resistance due to temperature is a:
Thermistor
Capacitive sensor
Accelerometer
Photodiode
Explanation - Thermistors vary their resistance with temperature changes.
Correct answer is: Thermistor
Q.82 Which sensor type would best measure the vibration of a heart valve?
Accelerometer
Strain gauge
Thermistor
Capacitive sensor
Explanation - Accelerometers are suitable for detecting dynamic vibration signatures.
Correct answer is: Accelerometer
Q.83 The term 'signal-to-noise ratio' (SNR) in biomedical sensors refers to:
The ratio of signal amplitude to noise amplitude
The ratio of sensor size to noise level
The ratio of power consumption to noise
The ratio of sensor cost to performance
Explanation - SNR quantifies how clear the desired signal is compared to background noise.
Correct answer is: The ratio of signal amplitude to noise amplitude
Q.84 Which sensor is most suitable for measuring the electrical potential across a small area of skin?
ECG electrode
Temperature sensor
Accelerometer
Thermistor
Explanation - ECG electrodes capture microvolt-level bioelectric potentials from the skin surface.
Correct answer is: ECG electrode
Q.85 What type of transducer is used to convert pressure into voltage in a pressure transducer?
Piezoelectric transducer
Thermocouple
Accelerometer
Photodiode
Explanation - Piezoelectric elements produce voltage when subjected to mechanical pressure.
Correct answer is: Piezoelectric transducer
Q.86 Which sensor technology is most commonly used to detect arterial pulse in a wristwatch?
PPG sensor
Accelerometer
Thermistor
Strain gauge
Explanation - PPG sensors measure blood volume changes in the wrist to estimate heart rate.
Correct answer is: PPG sensor
Q.87 Which of these sensors is best suited for detecting motion in a rehabilitation robot?
Accelerometer
Capacitive pressure sensor
Thermistor
Photodiode
Explanation - Accelerometers sense linear acceleration, providing data for motion control.
Correct answer is: Accelerometer
Q.88 A sensor that detects changes in light intensity due to blood volume changes is a:
PPG sensor
Accelerometer
Thermistor
Capacitive sensor
Explanation - PPG uses light absorption/reflection changes caused by arterial blood flow.
Correct answer is: PPG sensor
Q.89 What is the main advantage of using a fiber optic sensor over a metal sensor in an MRI environment?
High temperature tolerance
Lightweight construction
Immunity to magnetic fields
High electrical conductivity
Explanation - Fiber optics do not interact with magnetic fields, making them safe for MRI use.
Correct answer is: Immunity to magnetic fields
Q.90 Which sensor is used to detect the presence of CO₂ in a ventilator circuit?
Metal-oxide sensor
Thermistor
Accelerometer
Capacitive pressure sensor
Explanation - Metal-oxide sensors are responsive to CO₂ concentration and suitable for ventilation monitoring.
Correct answer is: Metal-oxide sensor
Q.91 The primary output of an electrochemical biosensor is:
Voltage
Current
Resistance
Frequency
Explanation - Electrochemical biosensors typically produce a current proportional to analyte concentration.
Correct answer is: Current
Q.92 Which sensor would detect a patient’s pulse without direct skin contact?
PPG sensor
Accelerometer
Thermistor
Capacitive sensor
Explanation - PPG can be positioned over a vein or artery to measure pulse without contact.
Correct answer is: PPG sensor
Q.93 What is the main benefit of using a MEMS pressure sensor in a wearable blood pressure monitor?
High cost
Large form factor
Low power consumption
Limited accuracy
Explanation - MEMS sensors are energy efficient, essential for battery-powered wearables.
Correct answer is: Low power consumption
Q.94 In a cardiac pacemaker, what is the purpose of the sensing electrode?
To deliver electrical pulses
To detect heart rate
To monitor temperature
To measure blood pressure
Explanation - Sensing electrodes monitor the heart's electrical activity to trigger pacing as needed.
Correct answer is: To detect heart rate
Q.95 Which sensor type is used in a respiratory monitor to measure airflow velocity?
Anemometer (hot-wire)
Pressure sensor
Thermistor
Capacitive sensor
Explanation - Hot-wire anemometers sense airflow via convective cooling of a heated wire.
Correct answer is: Anemometer (hot-wire)
Q.96 Which of these transducers measures changes in temperature by measuring changes in resistance?
RTD
Thermistor
Thermocouple
Optical fiber sensor
Explanation - Thermistors are resistive temperature sensors that change resistance with temperature.
Correct answer is: Thermistor
Q.97 Which sensor would best detect the presence of a metallic implant during surgery?
Inductive proximity sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Inductive sensors sense metal via magnetic field changes, useful for implant detection.
Correct answer is: Inductive proximity sensor
Q.98 A sensor that converts mechanical pressure into a change in capacitance is a:
Capacitive pressure sensor
Strain gauge sensor
Thermistor
Photodiode
Explanation - Capacitive sensors measure pressure-induced changes in capacitance between plates.
Correct answer is: Capacitive pressure sensor
Q.99 What is the main disadvantage of using a thermistor for deep tissue temperature monitoring?
Limited depth penetration
High cost
Large size
High power consumption
Explanation - Thermistors are surface-based; they cannot sense deep tissue temperature without invasive placement.
Correct answer is: Limited depth penetration
Q.100 Which sensor technology is used to detect heart rate in a smartwatch using optical methods?
PPG sensor
Accelerometer
Thermistor
Capacitive sensor
Explanation - PPG sensors emit light and detect reflected light changes to estimate heart rate.
Correct answer is: PPG sensor
Q.101 The primary output of a thermocouple is a voltage that is proportional to:
Temperature difference between junctions
Absolute temperature of the junctions
Temperature gradient along the wire
Ambient humidity
Explanation - Thermocouples generate voltage based on the Seebeck effect due to the temperature difference.
Correct answer is: Temperature difference between junctions
Q.102 Which of the following best describes a fiber Bragg grating sensor?
It measures voltage changes in response to pressure
It reflects a specific wavelength that shifts with strain or temperature
It is a type of thermocouple
It uses magnetic fields to detect metal proximity
Explanation - FBG sensors rely on wavelength shifts in reflected light to sense strain or temperature.
Correct answer is: It reflects a specific wavelength that shifts with strain or temperature
Q.103 In a medical ultrasound probe, which type of transducer converts electrical signals into sound waves?
Piezoelectric transducer
Thermistor
Accelerometer
Capacitive sensor
Explanation - Piezoelectric elements produce sound when voltage is applied, used in ultrasound imaging.
Correct answer is: Piezoelectric transducer
Q.104 What is the purpose of a low-pass filter in an ECG signal chain?
To remove high-frequency noise
To amplify the ECG signal
To block DC offset
To convert analog to digital
Explanation - Low-pass filters limit bandwidth, removing high-frequency noise from the ECG signal.
Correct answer is: To remove high-frequency noise
Q.105 Which sensor would be most suitable for measuring the temperature of a surgical incision?
Thermistor
Accelerometer
Capacitive pressure sensor
Thermocouple
Explanation - Thermistors provide rapid and accurate temperature measurements on small surfaces.
Correct answer is: Thermistor
Q.106 What is the main function of an electret microphone in a medical hearing aid?
To amplify sound
To convert acoustic vibrations into electrical signals
To measure temperature
To detect motion
Explanation - The electret mic converts sound pressure into a voltage signal for processing.
Correct answer is: To convert acoustic vibrations into electrical signals
Q.107 Which of the following is a characteristic of a piezoelectric sensor?
It requires a voltage source to operate
It generates charge when mechanically stressed
It is unaffected by temperature changes
It uses magnetic fields for detection
Explanation - Piezoelectric sensors produce charge directly from applied mechanical stress.
Correct answer is: It generates charge when mechanically stressed
Q.108 Which sensor would be used to detect the presence of a gas in a medical environment?
Metal-oxide semiconductor sensor
Thermistor
Accelerometer
Capacitive pressure sensor
Explanation - MOS sensors change resistance with gas concentration, useful for detecting hazardous gases.
Correct answer is: Metal-oxide semiconductor sensor
Q.109 What is the primary advantage of using a MEMS gyroscope over a mechanical gyroscope in a wearable device?
Higher power consumption
Lower sensitivity
Compact size and low cost
Higher temperature tolerance
Explanation - MEMS gyroscopes are small, inexpensive, and integrate well with other electronics.
Correct answer is: Compact size and low cost
Q.110 Which of the following is an advantage of using a fiber optic sensor for temperature measurement?
High electrical conductivity
Immunity to electromagnetic interference
Large size
High power consumption
Explanation - Fiber optics are immune to EMI, ideal for harsh medical environments.
Correct answer is: Immunity to electromagnetic interference
Q.111 In a continuous glucose monitor, what is the role of the reference electrode?
To supply power
To provide a stable reference potential
To sense temperature
To detect motion
Explanation - The reference electrode establishes a baseline potential for accurate electrochemical measurement.
Correct answer is: To provide a stable reference potential
Q.112 A sensor that uses a change in light intensity to measure blood flow is a:
PPG sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - PPG sensors detect changes in light intensity caused by arterial blood flow.
Correct answer is: PPG sensor
Q.113 Which sensor technology is most suitable for measuring pressure in a catheter for monitoring intracranial pressure?
Capacitive pressure sensor
Thermistor
Accelerometer
Optical sensor
Explanation - Capacitive sensors can be miniaturized for intravascular and intracranial applications.
Correct answer is: Capacitive pressure sensor
Q.114 What does a differential amplifier do in a biomedical sensor system?
Amplifies the common-mode signal
Amplifies the difference between two inputs while rejecting common-mode noise
Converts analog to digital
Filters out all signals
Explanation - Differential amplifiers enhance useful signals and suppress shared noise.
Correct answer is: Amplifies the difference between two inputs while rejecting common-mode noise
Q.115 Which sensor is used to measure the oxygen concentration in the blood for an arterial blood gas analyzer?
Electrochemical sensor
Optical absorption sensor
Capacitive sensor
Thermistor
Explanation - Blood gas analyzers use electrochemical electrodes to determine PaO₂ values.
Correct answer is: Electrochemical sensor
Q.116 Which type of sensor is best for detecting the presence of a metal rod in a surgical field?
Inductive proximity sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Inductive sensors detect metal via magnetic fields, ideal for surgical instrument detection.
Correct answer is: Inductive proximity sensor
Q.117 A sensor that measures changes in pressure by monitoring the deformation of a diaphragm is a:
Capacitive pressure sensor
Strain gauge sensor
Thermistor
Accelerometer
Explanation - Diaphragm deformation changes the capacitance between plates, yielding a pressure measurement.
Correct answer is: Capacitive pressure sensor
Q.118 The main advantage of using a MEMS-based accelerometer in a fall detection wearable is:
High power consumption
Large size
Low cost and high integration
Limited accuracy
Explanation - MEMS accelerometers are small, low-power, and inexpensive, enabling mass deployment.
Correct answer is: Low cost and high integration
Q.119 Which of the following is a common source of noise in ECG recordings?
Motion artifacts
Ambient light
High-frequency electromagnetic interference
Both A and C
Explanation - Motion artifacts and EMI are typical noise sources affecting ECG signal quality.
Correct answer is: Both A and C
Q.120 Which sensor technology is used to measure the concentration of hydrogen peroxide in a medical device?
Electrochemical sensor
Capacitive sensor
Optical sensor
Thermistor
Explanation - Electrochemical sensors detect peroxide via redox reactions, producing measurable current.
Correct answer is: Electrochemical sensor
Q.121 What is the main function of a photodiode in a pulse oximeter?
Generate light
Detect light intensity
Measure temperature
Sense pressure
Explanation - The photodiode converts incident light into an electrical current proportional to intensity.
Correct answer is: Detect light intensity
Q.122 Which sensor type measures the change in capacitance caused by a dielectric material moving between two plates?
Capacitive sensor
Strain gauge sensor
Thermistor
Photodiode
Explanation - Capacitive sensors detect changes in dielectric constant, used for humidity or proximity detection.
Correct answer is: Capacitive sensor
Q.123 A sensor that monitors the concentration of nitrogen oxides (NOx) in ambient air uses which technology?
Electrochemical sensor
Metal-oxide sensor
Thermistor
Accelerometer
Explanation - NOx sensors often rely on MOS technology due to its sensitivity to oxidizing gases.
Correct answer is: Metal-oxide sensor
Q.124 Which of the following best describes a strain gauge sensor?
It detects changes in magnetic field
It measures changes in electrical resistance due to deformation
It measures changes in light intensity
It measures temperature via resistance change
Explanation - Strain gauges convert mechanical deformation into changes in resistance.
Correct answer is: It measures changes in electrical resistance due to deformation
Q.125 In a medical ventilation system, which sensor monitors the flow rate of air?
Hot-wire anemometer
Capacitive pressure sensor
Thermistor
Accelerometer
Explanation - Hot-wire anemometers measure airflow velocity via cooling of a heated element.
Correct answer is: Hot-wire anemometer
Q.126 A sensor that uses the Hall effect to detect magnetic field changes is known as a:
Hall-effect sensor
Accelerometer
Thermistor
Capacitive sensor
Explanation - Hall-effect sensors produce a voltage proportional to magnetic field strength.
Correct answer is: Hall-effect sensor
Q.127 Which of the following is a primary advantage of using an electrochemical biosensor over a physical sensor?
Higher power consumption
Direct chemical analysis
Non-selective detection
Large size
Explanation - Biosensors detect specific biochemical interactions, providing selective analysis.
Correct answer is: Direct chemical analysis
Q.128 In a blood glucose monitor, what is the role of the enzyme glucose oxidase?
To generate light
To catalyze the oxidation of glucose to produce a measurable current
To provide structural support
To measure temperature
Explanation - Glucose oxidase oxidizes glucose, generating electrons that produce current.
Correct answer is: To catalyze the oxidation of glucose to produce a measurable current
Q.129 Which sensor type measures the change in resistance due to temperature?
Thermistor
Accelerometer
Capacitive sensor
Photodiode
Explanation - Thermistors change their electrical resistance in response to temperature changes.
Correct answer is: Thermistor
Q.130 Which of the following is a typical application of a fiber optic pressure sensor?
Measuring blood pressure in a catheter
Detecting motion in a robot
Measuring temperature in a wound
Monitoring ambient light levels
Explanation - Fiber optic pressure sensors are used for intravascular pressure monitoring due to their small size and EMI immunity.
Correct answer is: Measuring blood pressure in a catheter
Q.131 Which type of sensor would best measure the electrical activity of the heart?
ECG electrode
Accelerometer
Thermistor
Capacitive pressure sensor
Explanation - ECG electrodes capture the heart’s electrical potentials directly.
Correct answer is: ECG electrode
Q.132 What is the primary purpose of a temperature sensor in a cryotherapy device?
To monitor patient temperature and ensure safety
To measure blood flow
To detect motion
To measure pressure
Explanation - Temperature monitoring ensures cryotherapy does not overcool tissue.
Correct answer is: To monitor patient temperature and ensure safety
Q.133 Which sensor technology measures the bending of a flexible substrate?
Strain gauge
Thermistor
Accelerometer
Capacitive sensor
Explanation - Strain gauges detect bending through resistance changes in a conductive path.
Correct answer is: Strain gauge
Q.134 What is the key function of a reference electrode in an electrochemical biosensor?
To supply power
To provide a stable electrical potential against which measurements are taken
To detect temperature
To amplify the signal
Explanation - The reference electrode provides a fixed potential reference for accurate current measurement.
Correct answer is: To provide a stable electrical potential against which measurements are taken
Q.135 Which sensor would be most suitable for measuring the pressure of a patient's blood during a cardiac catheterization?
Capacitive pressure sensor
Thermistor
Accelerometer
Optical sensor
Explanation - Capacitive pressure sensors can be miniaturized to fit into catheters for intravascular pressure measurement.
Correct answer is: Capacitive pressure sensor
Q.136 Which sensor type uses a change in dielectric constant to detect moisture?
Capacitive humidity sensor
Strain gauge sensor
Thermistor
Accelerometer
Explanation - Capacitive humidity sensors detect moisture via changes in capacitance between electrodes.
Correct answer is: Capacitive humidity sensor
Q.137 A sensor that measures the voltage change due to light absorption by blood is a:
PPG sensor
Accelerometer
Thermistor
Capacitive sensor
Explanation - PPG sensors measure the light absorption changes caused by arterial blood flow.
Correct answer is: PPG sensor
Q.138 What is the main advantage of using a fiber optic sensor in a high-EMI environment?
High temperature tolerance
Immunity to electromagnetic interference
Low cost
Large size
Explanation - Fiber optics do not conduct electricity, preventing EMI interference in medical settings.
Correct answer is: Immunity to electromagnetic interference
Q.139 Which sensor is used to detect changes in pressure inside the ear canal during a hearing aid test?
Capacitive pressure sensor
Thermistor
Accelerometer
Optical sensor
Explanation - Capacitive sensors accurately detect subtle pressure variations within the ear canal.
Correct answer is: Capacitive pressure sensor
Q.140 What is the main role of a band-pass filter in a biomedical signal processing chain?
To amplify the entire signal
To allow only frequencies within a specific range while blocking others
To convert analog to digital
To increase noise level
Explanation - Band-pass filters isolate the desired signal band, removing unwanted low and high frequencies.
Correct answer is: To allow only frequencies within a specific range while blocking others
Q.141 Which sensor would best measure the presence of a metallic implant during a surgical procedure?
Inductive proximity sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Inductive sensors detect metal by changes in magnetic field coupling, ideal for implant detection.
Correct answer is: Inductive proximity sensor
Q.142 A sensor that uses a change in light intensity to detect blood oxygen levels is a:
Photoplethysmograph (PPG)
Accelerometer
Thermistor
Capacitive pressure sensor
Explanation - PPG measures changes in light absorption due to varying blood volume.
Correct answer is: Photoplethysmograph (PPG)
Q.143 Which sensor technology is used to measure the concentration of ammonia in breath for a medical device?
Metal-oxide semiconductor sensor
Thermistor
Accelerometer
Capacitive pressure sensor
Explanation - MOS sensors detect ammonia concentration through changes in resistance.
Correct answer is: Metal-oxide semiconductor sensor
Q.144 What is the main function of a thermistor in a wound dressing device?
To measure temperature
To detect motion
To monitor humidity
To measure blood pressure
Explanation - Thermistors accurately track temperature changes in a wound to monitor healing.
Correct answer is: To measure temperature
Q.145 A sensor that uses a change in capacitance to detect the presence of a liquid inside a catheter is a:
Capacitive sensor
Accelerometer
Thermistor
Photodiode
Explanation - Capacitive sensors can detect changes in dielectric constant when liquid enters a catheter.
Correct answer is: Capacitive sensor
Q.146 Which type of sensor is best suited for measuring the force applied by a patient on a rehabilitation device?
Load cell
Accelerometer
Thermistor
Photodiode
Explanation - Load cells provide accurate force measurement for rehabilitation applications.
Correct answer is: Load cell
Q.147 What is the primary advantage of using a MEMS gyroscope in a wearable fitness tracker?
High power consumption
Large size
Compact size and low cost
Low accuracy
Explanation - MEMS gyroscopes are small, inexpensive, and integrate well with other electronics.
Correct answer is: Compact size and low cost
Q.148 A sensor that monitors the amount of blood flow in a microfluidic chip is likely a:
Capacitive pressure sensor
Strain gauge sensor
Thermistor
Optical sensor
Explanation - Capacitive pressure sensors can detect minute pressure changes associated with fluid flow.
Correct answer is: Capacitive pressure sensor
Q.149 Which sensor technology is most appropriate for detecting the presence of a metallic implant in a catheter-based system?
Inductive proximity sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Inductive sensors detect metal via magnetic field changes.
Correct answer is: Inductive proximity sensor
Q.150 What does an ADC stand for in biomedical instrumentation?
Analog-to-Digital Converter
Amplifier-to-Data Converter
Acoustic-Detection Circuit
Array Data Collector
Explanation - An ADC samples analog voltage and produces a digital representation for processing.
Correct answer is: Analog-to-Digital Converter
Q.151 Which sensor type would best measure the temperature of a surgical incision during a procedure?
Thermistor
Accelerometer
Capacitive pressure sensor
Thermocouple
Explanation - Thermistors provide rapid, accurate temperature readings on small surfaces.
Correct answer is: Thermistor
Q.152 What is the primary advantage of using a fiber optic temperature sensor in a high-temperature medical device?
High electrical conductivity
Immunity to electromagnetic interference
Large size
High power consumption
Explanation - Fiber optic sensors are immune to EMI, making them reliable in high-temperature environments.
Correct answer is: Immunity to electromagnetic interference
Q.153 Which sensor technology is commonly used to measure the concentration of glucose in the blood for a diabetic patient?
Electrochemical biosensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Glucose monitors use enzymatic electrochemical reactions to produce a measurable current.
Correct answer is: Electrochemical biosensor
Q.154 What is the main function of a differential amplifier in a biomedical signal chain?
Amplify the common-mode signal
Amplify the difference between two inputs while rejecting common-mode noise
Convert analog to digital
Filter out all signals
Explanation - Differential amplifiers enhance useful signals and suppress shared noise.
Correct answer is: Amplify the difference between two inputs while rejecting common-mode noise
Q.155 Which sensor type is best for detecting the presence of a metallic rod in a surgical field?
Inductive proximity sensor
Capacitive sensor
Thermistor
Accelerometer
Explanation - Inductive sensors detect metal via magnetic fields.
Correct answer is: Inductive proximity sensor