Q.1 Which of the following signals is used to record the electrical activity of the heart?
EEG
ECG
EMG
EOG
Explanation - ECG (Electrocardiogram) records the electrical activity of the heart, whereas EEG records brain activity, EMG records muscle activity, and EOG records eye movements.
Correct answer is: ECG
Q.2 What type of electrode is typically used for long‑term ECG monitoring?
Dry adhesive electrode
Skin contact electrode
Wet gel electrode
Surface electrode
Explanation - Wet gel electrodes provide a low impedance and stable contact for long‑term ECG recording, whereas dry or surface electrodes may drift over time.
Correct answer is: Wet gel electrode
Q.3 The amplitude of the QRS complex in a normal ECG is typically:
0.1–0.5 mV
0.5–1.5 mV
1.5–3.0 mV
3.0–5.0 mV
Explanation - The QRS complex generally has an amplitude of about 0.5–1.5 mV in adults under normal conditions.
Correct answer is: 0.5–1.5 mV
Q.4 Pulse oximetry measures which of the following?
Heart rate
Blood oxygen saturation
Blood pressure
Respiratory rate
Explanation - Pulse oximeters use light absorption to estimate arterial oxygen saturation (SpO2), not directly measuring heart rate, blood pressure or respiration.
Correct answer is: Blood oxygen saturation
Q.5 Which wavelength pair is used by a typical pulse oximeter?
660 nm and 940 nm
520 nm and 620 nm
700 nm and 800 nm
450 nm and 550 nm
Explanation - Pulse oximeters use red (≈660 nm) and infrared (≈940 nm) LEDs because oxyhemoglobin and deoxyhemoglobin have different absorption at these wavelengths.
Correct answer is: 660 nm and 940 nm
Q.6 Which of the following best describes the Nyquist criterion?
Sampling frequency must be at least twice the highest frequency in the signal
Signal should be sampled at the same rate as its frequency
The sampling frequency must be a multiple of the signal frequency
Sampling frequency has no relation to the signal frequency
Explanation - The Nyquist theorem states that to avoid aliasing, the sampling rate must be greater than twice the highest frequency component of the signal.
Correct answer is: Sampling frequency must be at least twice the highest frequency in the signal
Q.7 What is the typical bandwidth of a standard ECG lead?
0.05–100 Hz
0.5–100 Hz
0.05–150 Hz
0.5–200 Hz
Explanation - Standard ECG filters usually pass frequencies from about 0.05 Hz to 100 Hz to capture the main features of the cardiac waveform.
Correct answer is: 0.05–100 Hz
Q.8 Which sensor is used to measure intra‑ocular pressure?
Tonometer
Tonometer
Barometer
Manometer
Explanation - A tonometer measures intra‑ocular pressure; barometers measure atmospheric pressure and manometers measure pressure in fluid systems.
Correct answer is: Tonometer
Q.9 The time interval between the start of the Q wave and the end of the T wave is called:
QT interval
PR interval
RR interval
QRS duration
Explanation - The QT interval represents ventricular depolarization and repolarization from the beginning of Q to the end of T.
Correct answer is: QT interval
Q.10 Which of the following is NOT a typical cause of high impedance in ECG electrodes?
Dry skin
Low electrode contact
Excessive gel
Poor electrode placement
Explanation - Too much gel can actually lower impedance; dry skin, low contact, and poor placement increase impedance.
Correct answer is: Excessive gel
Q.11 In an EEG, the alpha rhythm is most prominent when:
Eyes are open during relaxation
Eyes are closed during relaxation
Subject is actively thinking
Subject is sleeping
Explanation - Alpha waves (8–13 Hz) are strongest with eyes closed and relaxed wakefulness.
Correct answer is: Eyes are closed during relaxation
Q.12 What does the AAMI ISO 80601‑2‑61 standard address?
Quality of pulse oximeters
Electrical safety of medical devices
Calibration of ECG machines
Clinical trial protocols
Explanation - AAMI ISO 80601‑2‑61 specifies performance requirements for pulse oximeters.
Correct answer is: Quality of pulse oximeters
Q.13 Which parameter is NOT part of the blood gas analysis?
pH
pCO₂
pO₂
pH₂O
Explanation - Blood gas analysis measures pH, pCO₂, pO₂, bicarbonate, etc., but not a separate pH₂O value.
Correct answer is: pH₂O
Q.14 Which of these is a non‑invasive method to estimate intracranial pressure?
Transcranial Doppler
Invasive lumbar puncture
CT scan
MRI
Explanation - Transcranial Doppler measures blood flow velocity and can provide indirect estimates of intracranial pressure.
Correct answer is: Transcranial Doppler
Q.15 What does the term “beat‑to‑beat variability” refer to in ECG analysis?
Variation in heart rate over months
Variation in the length of each cardiac cycle
Variation in signal amplitude between beats
Variation in electrode placement
Explanation - Beat‑to‑beat variability refers to the changes in RR interval from one heartbeat to the next.
Correct answer is: Variation in the length of each cardiac cycle
Q.16 Which of the following is a key advantage of a 12‑lead ECG over a single‑lead ECG?
Simpler equipment
Lower cost
More anatomical detail
Faster acquisition
Explanation - A 12‑lead ECG provides spatial information about the heart’s electrical activity, whereas single‑lead only gives a limited view.
Correct answer is: More anatomical detail
Q.17 What is the main cause of the “T wave” inversion seen after myocardial infarction?
Reperfusion injury
Hyperkalemia
Electrode misplacement
Low blood glucose
Explanation - Post‑infarction T wave inversion is usually due to myocardial stunning and reperfusion changes.
Correct answer is: Reperfusion injury
Q.18 In impedance cardiography, what is measured to estimate stroke volume?
Blood pressure
Electrical impedance of thorax
Heart rate
Pulse wave velocity
Explanation - Impedance cardiography monitors changes in thoracic impedance during a heartbeat to derive stroke volume.
Correct answer is: Electrical impedance of thorax
Q.19 Which of the following is the most common cause of a high QRS amplitude in a lead?
Low electrode impedance
High electrode impedance
Lead misplacement
Low body temperature
Explanation - Incorrect lead placement can result in abnormal QRS amplitude due to altered vector orientation.
Correct answer is: Lead misplacement
Q.20 Which filter is typically used in ECG signal acquisition to remove baseline wander?
High‑pass filter at 0.5 Hz
Band‑pass filter 0.05–100 Hz
Low‑pass filter at 10 Hz
Notch filter at 60 Hz
Explanation - A high‑pass filter around 0.5 Hz eliminates slow baseline drift while preserving the ECG waveform.
Correct answer is: High‑pass filter at 0.5 Hz
Q.21 What does the term “saturation index” refer to in pulse oximetry?
Ratio of oxygenated to total hemoglobin
Ratio of arterial to venous oxygenation
Ratio of light absorption at 660 nm to 940 nm
Ratio of heart rate to blood pressure
Explanation - Pulse oximeters compute SpO₂ by comparing absorption ratios at two wavelengths.
Correct answer is: Ratio of light absorption at 660 nm to 940 nm
Q.22 Which of these is a common artifact in EEG recordings?
Muscle activity (EMG)
Lead noise
Cardiac rhythm (ECG)
All of the above
Explanation - EMG, ECG, and electrical interference are typical EEG artifacts.
Correct answer is: All of the above
Q.23 Which instrument is used to measure intra‑arterial blood pressure?
Sphygmomanometer
Catheter with pressure transducer
Oscillometer
Non‑invasive cuff
Explanation - Invasive intra‑arterial monitoring requires a catheter and transducer; non‑invasive devices estimate pressure indirectly.
Correct answer is: Catheter with pressure transducer
Q.24 What is the typical range of heart rate variability (HRV) in seconds for a healthy adult?
0.1–0.5 s
0.5–1.5 s
1.5–3.0 s
3.0–5.0 s
Explanation - Normal HRV values for adults usually lie between 0.5 and 1.5 seconds.
Correct answer is: 0.5–1.5 s
Q.25 Which of the following best describes the function of a bio‑impedance analyzer?
Measure blood oxygenation
Measure tissue resistance to an electrical current
Measure heart electrical activity
Measure skin temperature
Explanation - Bio‑impedance devices apply a small current to tissues and measure the resulting voltage to infer resistance and capacitance.
Correct answer is: Measure tissue resistance to an electrical current
Q.26 What is the main purpose of the A/D conversion in a biomedical sensor?
To amplify the analog signal
To filter high‑frequency noise
To convert analog signals to digital for processing
To calibrate the sensor
Explanation - Analog‑to‑Digital (A/D) converters translate continuous voltage signals into discrete digital values.
Correct answer is: To convert analog signals to digital for processing
Q.27 Which type of filter is used to remove 50/60 Hz power line interference?
High‑pass filter
Low‑pass filter
Band‑stop (Notch) filter
Band‑pass filter
Explanation - A notch filter attenuates a narrow frequency band, typically at the mains frequency.
Correct answer is: Band‑stop (Notch) filter
Q.28 Which sensor is commonly used to measure skin temperature in biomedical instrumentation?
Thermocouple
Thermistor
Heat flux sensor
Capacitive sensor
Explanation - Thermistors provide high‑sensitivity temperature measurement and are widely used in biomedical devices.
Correct answer is: Thermistor
Q.29 In blood pressure cuff measurement, the cuff inflation pressure should be:
At least 20 mmHg above systolic
At least 20 mmHg above diastolic
Exactly equal to systolic pressure
Equal to mean arterial pressure
Explanation - Inflating above systolic ensures occlusion; too high can cause discomfort.
Correct answer is: At least 20 mmHg above systolic
Q.30 What is the typical sampling rate for an EEG recording?
250 Hz
500 Hz
1000 Hz
2000 Hz
Explanation - EEG systems often sample at 250–500 Hz to capture brain waves up to ~70–80 Hz.
Correct answer is: 500 Hz
Q.31 Which component of a pulse oximeter is responsible for generating the LED light?
Photodiode
Microcontroller
LED driver circuit
Power supply
Explanation - The LED driver provides current pulses to the LEDs which produce the required light.
Correct answer is: LED driver circuit
Q.32 Which parameter is NOT directly measured by an ECG?
Heart rate
PR interval
QT interval
Blood glucose level
Explanation - ECG measures electrical activity of the heart, not metabolic parameters like glucose.
Correct answer is: Blood glucose level
Q.33 Which of the following is a disadvantage of dry electrodes?
Higher impedance
Less skin irritation
Longer contact time
Higher cost
Explanation - Dry electrodes often have higher contact impedance compared to gel‑based electrodes.
Correct answer is: Higher impedance
Q.34 What does the term “sensitivity” refer to in a biomedical sensor?
Minimum detectable change
Signal-to-noise ratio
Dynamic range
Linear output range
Explanation - Sensitivity is the smallest change in the measured quantity that yields a measurable change in output.
Correct answer is: Minimum detectable change
Q.35 The standard reference electrode for EEG recording is:
AFz
A1
A2
A0
Explanation - A1 (and A2) are standard ear electrodes used as reference for EEG; A0 is not a standard site.
Correct answer is: A1
Q.36 Which of the following is a typical source of motion artifact in ECG?
Finger tapping
Patient breathing
Cable movement
All of the above
Explanation - All listed movements can introduce artifacts into ECG recordings.
Correct answer is: All of the above
Q.37 The term “pulse pressure” refers to:
Difference between systolic and diastolic pressures
The absolute value of systolic pressure
The absolute value of diastolic pressure
The mean arterial pressure
Explanation - Pulse pressure equals systolic minus diastolic arterial pressure.
Correct answer is: Difference between systolic and diastolic pressures
Q.38 Which of the following is a common calibration method for a blood pressure cuff?
Using a known reference pressure
Using a calibration phantom
Using a standard weight
Using a thermometer
Explanation - Calibrating with a known pressure ensures accurate cuff readings.
Correct answer is: Using a known reference pressure
Q.39 Which of the following best defines a 'signal-to-noise ratio' (SNR) in biomedical instrumentation?
Ratio of signal amplitude to background noise power
Ratio of electrode impedance to skin resistance
Ratio of heart rate to breathing rate
Ratio of bandwidth to sampling frequency
Explanation - SNR quantifies how well a signal stands out from noise.
Correct answer is: Ratio of signal amplitude to background noise power
Q.40 The standard lead I ECG measures electrical activity between:
Right arm and left arm
Right arm and left leg
Left arm and left leg
Right arm and right leg
Explanation - Lead I measures potential difference between RA and LA.
Correct answer is: Right arm and left arm
Q.41 Which of the following is a key factor affecting the accuracy of a pulse oximeter?
Ambient temperature
Motion of the patient
Skin pigmentation
All of the above
Explanation - Temperature, motion, and skin pigmentation can all influence pulse oximeter readings.
Correct answer is: All of the above
Q.42 In an ECG, what does the T wave represent?
Ventricular depolarization
Ventricular repolarization
Atrial depolarization
Atrial repolarization
Explanation - The T wave corresponds to the recovery of ventricular muscle cells.
Correct answer is: Ventricular repolarization
Q.43 Which of the following is a typical measurement range for a capnograph?
0–5 kPa
1–5 kPa
4–8 kPa
8–12 kPa
Explanation - Capnography measures CO₂ partial pressure in the range of about 4–8 kPa (~30–60 mmHg).
Correct answer is: 4–8 kPa
Q.44 What does the term “analog front‑end” (AFE) refer to in biomedical instrumentation?
The part that digitizes signals
The part that amplifies, filters, and conditions analog signals
The part that displays signals on a screen
The part that stores data
Explanation - AFE processes raw sensor outputs before they are digitized.
Correct answer is: The part that amplifies, filters, and conditions analog signals
Q.45 Which of the following is a non‑invasive method to estimate arterial blood pressure?
Oscillometric cuff
Invasive catheter
Phlebotomy
Blood gas analysis
Explanation - Oscillometric methods estimate pressure using cuff inflation and oscillations.
Correct answer is: Oscillometric cuff
Q.46 Which of the following sensors measures the electrical potential difference between the skin and a reference point?
Electrocardiograph (ECG)
Electroencephalograph (EEG)
Electrooculograph (EOG)
All of the above
Explanation - All these devices measure skin potentials relative to a reference electrode.
Correct answer is: All of the above
Q.47 In a typical ECG, the P wave represents:
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
Explanation - The P wave corresponds to the electrical activity of the atria.
Correct answer is: Atrial depolarization
Q.48 Which of the following best describes a 'band‑pass filter' used in ECG acquisition?
Passes frequencies between 0.05–100 Hz
Passes frequencies below 0.05 Hz
Passes frequencies above 100 Hz
Passes all frequencies
Explanation - A band‑pass filter allows the ECG frequency range while rejecting low‑frequency drift and high‑frequency noise.
Correct answer is: Passes frequencies between 0.05–100 Hz
Q.49 What is the primary purpose of a calibration phantom in biomedical instrumentation?
To simulate physiological signals with known properties
To provide a physical reference for mechanical parts
To test the durability of the device
To calibrate the user interface
Explanation - Calibration phantoms replicate known bio‑signals for validating measurement accuracy.
Correct answer is: To simulate physiological signals with known properties
Q.50 Which of the following parameters is NOT part of a standard EEG recording protocol?
Montage configuration
Impedance checking
Use of reference electrodes
Continuous blood glucose monitoring
Explanation - EEG protocols focus on electrode placement, impedance, and referencing, not glucose monitoring.
Correct answer is: Continuous blood glucose monitoring
Q.51 What is the typical response time for a capnograph sensor?
5–10 ms
50–100 ms
0.5–1 s
2–5 s
Explanation - Capnograph sensors respond within about half a second to changes in CO₂ levels.
Correct answer is: 0.5–1 s
Q.52 Which of the following is a typical use of a photoplethysmogram (PPG) sensor?
Measure heart rhythm
Measure arterial stiffness
Measure blood pressure directly
Measure brain waves
Explanation - PPG measures blood volume changes and can derive heart rate and rhythm.
Correct answer is: Measure heart rhythm
Q.53 In a 12‑lead ECG, which lead provides the most accurate assessment of the left ventricle?
Lead I
Lead II
Lead V5
Lead V6
Explanation - Lead V5 is positioned over the left ventricle and gives a detailed view of its activity.
Correct answer is: Lead V5
Q.54 Which of the following is a major limitation of pulse oximeters in neonates?
High skin pigmentation
Low perfusion
Large blood volume
High oxygen consumption
Explanation - Neonates often have lower peripheral perfusion, reducing signal quality.
Correct answer is: Low perfusion
Q.55 The R‑R interval variability is most closely related to:
Autonomic nervous system activity
Respiratory rate
Blood pressure
Body temperature
Explanation - R‑R variability reflects sympathetic and parasympathetic influences on the heart.
Correct answer is: Autonomic nervous system activity
Q.56 Which component of the ECG machine is responsible for removing high‑frequency noise?
High‑pass filter
Low‑pass filter
Notch filter
Amplifier
Explanation - Low‑pass filtering attenuates high‑frequency interference such as muscle artifacts.
Correct answer is: Low‑pass filter
Q.57 Which of the following best describes the term 'electrode impedance'?
Electrical resistance between two electrodes
Electrical capacitance across the electrode
Electrical resistance of the electrode material
Electrical impedance at the skin‑electrode interface
Explanation - Electrode impedance refers to the resistance and reactance at the skin‑electrode contact point.
Correct answer is: Electrical impedance at the skin‑electrode interface
Q.58 What is the primary purpose of an A/D converter’s reference voltage?
To set the maximum measurable voltage
To provide power to the converter
To adjust the sampling frequency
To filter the input signal
Explanation - The reference voltage defines the full‑scale range of the A/D converter.
Correct answer is: To set the maximum measurable voltage
Q.59 Which of the following is a typical artifact in pulse oximetry during exercise?
Motion artifact
Ambient light interference
Skin pigment absorption
Low electrode impedance
Explanation - Movement during exercise causes changes in signal amplitude and leads to artifact.
Correct answer is: Motion artifact
Q.60 The 'QRS duration' is a key parameter in ECG analysis. It primarily indicates:
Conduction speed through the ventricles
Time for atrial depolarization
Time for ventricular repolarization
Overall heart rate
Explanation - QRS duration reflects how quickly the ventricles depolarize.
Correct answer is: Conduction speed through the ventricles
Q.61 What does the 'lead II' ECG configuration measure?
RA to LA
RA to LL
LA to LL
LL to RA
Explanation - Lead II records the potential difference between the right arm (RA) and left leg (LL).
Correct answer is: RA to LL
Q.62 Which of the following is a potential consequence of high electrode impedance in ECG?
Increased noise
Stable baseline
Higher signal amplitude
Reduced heart rate detection
Explanation - High impedance leads to higher noise and reduced signal quality.
Correct answer is: Increased noise
Q.63 Which of the following is an example of a bi‑polar electrode configuration?
Single‑leg reference
All‑skin reference
Monopolar recording
Bipolar recording between two sites
Explanation - Bipolar ECG leads record the difference between two adjacent electrodes.
Correct answer is: Bipolar recording between two sites
Q.64 What type of noise is typically generated by a power supply at 50/60 Hz?
Thermal noise
Shot noise
White noise
Line frequency interference
Explanation - The mains supply introduces 50 or 60 Hz interference into biomedical signals.
Correct answer is: Line frequency interference
Q.65 Which of the following instruments is used for measuring arterial oxygen tension directly?
Pulse oximeter
Oximetry sensor
Blood gas analyzer
Capnograph
Explanation - Blood gas analyzers measure arterial O₂ pressure (PaO₂) directly.
Correct answer is: Blood gas analyzer
Q.66 Which of the following best describes the 'gain' of an amplifier in an AFE circuit?
Ratio of output voltage to input voltage
Time constant of the filter
Noise figure of the circuit
Impedance of the input
Explanation - Gain is defined as output over input in voltage amplifiers.
Correct answer is: Ratio of output voltage to input voltage
Q.67 In a pulse oximeter, the term 'SpO₂' refers to:
Peripheral capillary oxygen saturation
Systemic arterial oxygen saturation
Pulmonary arterial oxygen saturation
Spontaneous oxygen saturation
Explanation - SpO₂ is the estimate of arterial oxygen saturation derived from peripheral tissue.
Correct answer is: Peripheral capillary oxygen saturation
Q.68 Which of the following is a common cause of ECG T wave inversion?
Hypertension
Atrial fibrillation
Left ventricular hypertrophy
Hyperthyroidism
Explanation - LV hypertrophy can produce T wave inversions in certain leads.
Correct answer is: Left ventricular hypertrophy
Q.69 Which of the following best describes the 'electrocardiographic window' in an ECG recording?
Time interval of the QRS complex
Time interval used to display ECG
Time interval of the P wave
Time interval of the T wave
Explanation - The ECG window refers to the duration shown on the monitor for analysis.
Correct answer is: Time interval used to display ECG
Q.70 What is the purpose of a 'signal conditioning' stage in a biomedical instrument?
Convert analog to digital
Filter, amplify, and shape the signal
Store data in memory
Display the signal on an LCD
Explanation - Signal conditioning prepares the raw sensor output for further processing.
Correct answer is: Filter, amplify, and shape the signal
Q.71 Which of the following is a typical use of a photoplethysmographic sensor?
Heart rate detection
Respiratory rate monitoring
Blood glucose monitoring
Blood pressure measurement
Explanation - PPG sensors are commonly used to derive heart rate from pulse waveform.
Correct answer is: Heart rate detection
Q.72 In a 12‑lead ECG, lead V1 is placed over which anatomical location?
Right fourth intercostal space at sternum
Left fourth intercostal space at sternum
Right fourth intercostal space at the left sternal border
Left fourth intercostal space at the left sternal border
Explanation - Lead V1 is positioned in the right fourth intercostal space, directly over the sternum.
Correct answer is: Right fourth intercostal space at sternum
Q.73 Which of the following best explains the term 'aliasing' in signal sampling?
High frequency signals appear as lower frequencies
Low frequency signals are lost
Noise increases at high frequencies
Signal amplitude is reduced
Explanation - Aliasing occurs when a signal is undersampled, causing high‑frequency components to masquerade as low‑frequency ones.
Correct answer is: High frequency signals appear as lower frequencies
Q.74 What type of electrode is commonly used for long‑term ECG monitoring in ICU settings?
Dry adhesive electrode
Skin contact electrode
Wet gel electrode
Surface electrode
Explanation - Wet gel electrodes maintain low impedance for continuous monitoring.
Correct answer is: Wet gel electrode
Q.75 Which of the following is a potential effect of skin perspiration on ECG measurements?
Increased electrode impedance
Decreased electrode impedance
No effect
Electrode displacement
Explanation - Sweat can alter skin contact, raising electrode impedance and causing noise.
Correct answer is: Increased electrode impedance
Q.76 Which of the following is a key feature of a capacitive electrode for ECG?
Requires gel for good contact
Does not need direct skin contact
Sensitive to movement
High power consumption
Explanation - Capacitive electrodes separate the skin from the sensor with a dielectric layer.
Correct answer is: Does not need direct skin contact
Q.77 What is the function of an 'integrator' in a biomedical signal processing circuit?
Amplify signals
Filter out high‑frequency noise
Add a constant offset
Calculate area under a signal curve
Explanation - An integrator sums the input signal over time, effectively computing area.
Correct answer is: Calculate area under a signal curve
Q.78 In ECG, the PR interval is a marker for:
Atrial depolarization time
AV nodal conduction time
Ventricular repolarization time
QRS complex duration
Explanation - PR interval reflects the time from atrial depolarization to the beginning of ventricular depolarization.
Correct answer is: AV nodal conduction time
Q.79 Which of the following best explains the term 'electrochemical sensor' in biomedical instrumentation?
Measures voltage changes from chemical reactions
Measures magnetic flux from biological activity
Measures pressure via fluid displacement
Measures temperature via resistance change
Explanation - Electrochemical sensors detect changes in electrical potential resulting from chemical reactions.
Correct answer is: Measures voltage changes from chemical reactions
Q.80 In a capnography trace, the steep rise at the beginning of each breath is known as the:
Slope
Rise time
Ramp
Steepness
Explanation - The rapid increase in CO₂ concentration at inhalation is called the rise time.
Correct answer is: Rise time
Q.81 Which of the following is NOT a typical characteristic of an ECG amplifier?
High common‑mode rejection ratio (CMRR)
Low input bias current
High slew rate
High power consumption
Explanation - ECG amplifiers are designed for low power consumption to be used in portable devices.
Correct answer is: High power consumption
Q.82 Which of the following is a typical parameter for evaluating the performance of a pulse oximeter?
Response time
Power consumption
Color of the probe
Size of the display
Explanation - Response time indicates how quickly the oximeter reacts to changes in oxygenation.
Correct answer is: Response time
Q.83 In an ECG, a wide QRS complex typically indicates:
Sinus rhythm
Bundle branch block
Atrial fibrillation
Ventricular tachycardia
Explanation - A widened QRS reflects delayed ventricular conduction such as a bundle branch block.
Correct answer is: Bundle branch block
Q.84 Which of the following is a primary source of noise in ECG acquisition?
Muscle activity (EMG)
Respiratory movement
Power line interference
All of the above
Explanation - EMG, respiration, and mains noise all degrade ECG quality.
Correct answer is: All of the above
Q.85 Which of the following sensors is used for measuring blood volume changes at the fingertip?
Photoplethysmograph
Blood pressure cuff
Capnograph
Thermistor
Explanation - PPG measures blood volume changes in the microcirculation via optical methods.
Correct answer is: Photoplethysmograph
Q.86 The 'A‑wave' in an ECG corresponds to which cardiac event?
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
Explanation - The A‑wave is the atrial contraction wave seen in some ECG tracings.
Correct answer is: Atrial depolarization
Q.87 Which of the following is a typical range for the arterial pulse pressure in adults?
10–20 mmHg
20–30 mmHg
30–50 mmHg
50–70 mmHg
Explanation - Normal pulse pressure ranges from about 30 to 50 mmHg.
Correct answer is: 30–50 mmHg
Q.88 Which of the following best describes the role of a 'band‑stop filter' in ECG signal processing?
Passes frequencies in a specific band
Attenuates frequencies in a specific band
Amplifies frequencies in a specific band
Reduces signal amplitude across all frequencies
Explanation - A band‑stop filter removes unwanted frequency components, such as mains interference.
Correct answer is: Attenuates frequencies in a specific band
Q.89 Which of the following is NOT typically measured by a photoplethysmograph?
Heart rate
Pulse transit time
Blood pressure
Respiratory rate
Explanation - PPG provides heart rate and sometimes pulse transit time but not direct BP measurement.
Correct answer is: Blood pressure
Q.90 The term 'electrocardiogram' is abbreviated as:
EEG
ECG
EMG
EOG
Explanation - ECG stands for Electrocardiogram.
Correct answer is: ECG
Q.91 Which of the following is a common method to reduce motion artifact in a wearable ECG sensor?
Use of a rigid mounting platform
Increase the sampling rate
Add a low‑pass filter
All of the above
Explanation - Stabilizing the sensor and filtering can mitigate motion artifact.
Correct answer is: All of the above
Q.92 In a standard 12‑lead ECG, which lead is most useful for detecting inferior myocardial infarction?
Lead I
Lead II
Lead III
Lead V1
Explanation - Lead III views the inferior wall of the heart.
Correct answer is: Lead III
Q.93 Which of the following is a major advantage of using a capacitive electrode over a gel electrode for ECG?
Higher impedance
Longer skin contact time without drying
Lower cost
Higher signal amplitude
Explanation - Capacitive electrodes avoid gel drying and maintain stable impedance.
Correct answer is: Longer skin contact time without drying
Q.94 Which of the following is a common artifact in pulse oximetry when a patient moves their finger?
Pulse lag
Motion artifact
Baseline drift
Power line interference
Explanation - Finger movement changes the optical path and causes signal disturbances.
Correct answer is: Motion artifact
Q.95 Which of the following is NOT part of a standard blood gas analysis?
pH
pCO₂
pO₂
pN₂
Explanation - Blood gas tests do not measure nitrogen partial pressure.
Correct answer is: pN₂
Q.96 In a typical ECG, the ST segment is most often evaluated to detect:
Heart rate
Myocardial ischemia
Atrial fibrillation
Pulmonary embolism
Explanation - ST elevation or depression indicates myocardial injury or ischemia.
Correct answer is: Myocardial ischemia
Q.97 Which of the following is a key requirement for a high‑quality ECG recording?
Low electrode impedance
High sampling rate
Low filter cutoff
All of the above
Explanation - All listed factors contribute to high‑quality ECG signals.
Correct answer is: All of the above
Q.98 Which of the following devices is used for non‑invasive measurement of blood pressure?
Invasive catheter
Sphygmomanometer
Blood gas analyzer
Pulse oximeter
Explanation - Sphygmomanometers provide cuff‑based, non‑invasive BP readings.
Correct answer is: Sphygmomanometer
Q.99 Which of the following is a key factor influencing the accuracy of an EEG?
Skin preparation
Reference electrode choice
Impedance matching
All of the above
Explanation - All factors affect signal quality in EEG acquisition.
Correct answer is: All of the above
Q.100 Which of the following is a common artifact in an ECG recorded during deep respiration?
Baseline wander
Power line interference
High‑frequency noise
Capillary refill
Explanation - Respiratory motion causes slow baseline shifts in ECG.
Correct answer is: Baseline wander
Q.101 Which of the following is a typical measurement unit for blood pressure?
mmHg
kPa
Pa
All of the above
Explanation - Blood pressure is commonly expressed in millimeters of mercury.
Correct answer is: mmHg
Q.102 Which of the following best describes a 'band‑pass filter' used in ECG acquisition?
Passes frequencies between 0.05–100 Hz
Passes frequencies below 0.05 Hz
Passes frequencies above 100 Hz
Passes all frequencies
Explanation - A band‑pass filter allows the ECG frequency range while rejecting low‑frequency drift and high‑frequency noise.
Correct answer is: Passes frequencies between 0.05–100 Hz
Q.103 What does the term 'saturation index' refer to in pulse oximetry?
Ratio of oxygenated to total hemoglobin
Ratio of arterial to venous oxygenation
Ratio of light absorption at 660 nm to 940 nm
Ratio of heart rate to blood pressure
Explanation - Pulse oximeters compute SpO₂ by comparing absorption ratios at two wavelengths.
Correct answer is: Ratio of light absorption at 660 nm to 940 nm
Q.104 Which of the following is a common source of motion artifact in ECG?
Finger tapping
Patient breathing
Cable movement
All of the above
Explanation - All listed movements can introduce artifacts into ECG recordings.
Correct answer is: All of the above
Q.105 Which of the following is NOT a typical cause of high impedance in ECG electrodes?
Dry skin
Low electrode contact
Excessive gel
Poor electrode placement
Explanation - Too much gel can actually lower impedance; dry skin, low contact, and poor placement increase impedance.
Correct answer is: Excessive gel
Q.106 Which of the following parameters is NOT part of a standard EEG recording protocol?
Montage configuration
Impedance checking
Use of reference electrodes
Continuous blood glucose monitoring
Explanation - EEG protocols focus on electrode placement, impedance, and referencing, not glucose monitoring.
Correct answer is: Continuous blood glucose monitoring
Q.107 What is the typical response time for a capnograph sensor?
5–10 ms
50–100 ms
0.5–1 s
2–5 s
Explanation - Capnograph sensors respond within about half a second to changes in CO₂ levels.
Correct answer is: 0.5–1 s
Q.108 Which of the following is a typical use of a photoplethysmographic sensor?
Measure heart rhythm
Measure arterial stiffness
Measure blood pressure directly
Measure brain waves
Explanation - PPG measures blood volume changes and can derive heart rate and rhythm.
Correct answer is: Measure heart rhythm
Q.109 The main advantage of a 12‑lead ECG over a single‑lead ECG is:
Simpler equipment
Lower cost
More anatomical detail
Faster acquisition
Explanation - A 12‑lead ECG provides spatial information about the heart’s electrical activity, whereas single‑lead only gives a limited view.
Correct answer is: More anatomical detail
Q.110 Pulse oximetry measures which of the following?
Heart rate
Blood oxygen saturation
Blood pressure
Respiratory rate
Explanation - Pulse oximeters use light absorption to estimate arterial oxygen saturation (SpO2), not directly measuring heart rate, blood pressure or respiration.
Correct answer is: Blood oxygen saturation
Q.111 What is the typical sampling rate for an EEG recording?
250 Hz
500 Hz
1000 Hz
2000 Hz
Explanation - EEG systems often sample at 250–500 Hz to capture brain waves up to ~70–80 Hz.
Correct answer is: 500 Hz
Q.112 Which of the following best describes the term 'electrode impedance'?
Electrical resistance between two electrodes
Electrical capacitance across the electrode
Electrical resistance of the electrode material
Electrical impedance at the skin‑electrode interface
Explanation - Electrode impedance refers to the resistance and reactance at the skin‑electrode contact point.
Correct answer is: Electrical impedance at the skin‑electrode interface
Q.113 The term 'lead I ECG' measures electrical activity between which two body parts?
Right arm and left arm
Right arm and left leg
Left arm and left leg
Right arm and right leg
Explanation - Lead I measures potential difference between RA and LA.
Correct answer is: Right arm and left arm
Q.114 In a standard 12‑lead ECG, lead V1 is placed over which anatomical location?
Right fourth intercostal space at sternum
Left fourth intercostal space at sternum
Right fourth intercostal space at the left sternal border
Left fourth intercostal space at the left sternal border
Explanation - Lead V1 is positioned in the right fourth intercostal space, directly over the sternum.
Correct answer is: Right fourth intercostal space at sternum
Q.115 Which of the following is a typical measurement unit for blood pressure?
mmHg
kPa
Pa
All of the above
Explanation - Blood pressure is commonly expressed in millimeters of mercury.
Correct answer is: mmHg
Q.116 Which of the following best describes the term 'electrochemical sensor' in biomedical instrumentation?
Measures voltage changes from chemical reactions
Measures magnetic flux from biological activity
Measures pressure via fluid displacement
Measures temperature via resistance change
Explanation - Electrochemical sensors detect changes in electrical potential resulting from chemical reactions.
Correct answer is: Measures voltage changes from chemical reactions
Q.117 Which of the following is a common artifact in pulse oximetry during exercise?
Motion artifact
Ambient light interference
Skin pigment absorption
Low electrode impedance
Explanation - Movement during exercise causes changes in signal amplitude and leads to artifact.
Correct answer is: Motion artifact
Q.118 In ECG, the T wave represents:
Ventricular depolarization
Ventricular repolarization
Atrial depolarization
Atrial repolarization
Explanation - The T wave corresponds to the recovery of ventricular muscle cells.
Correct answer is: Ventricular repolarization
Q.119 Which of the following is NOT a typical source of noise in ECG acquisition?
EMG
Respiration
Mains interference
Blood glucose fluctuations
Explanation - Blood glucose changes do not directly introduce electrical noise into ECG signals.
Correct answer is: Blood glucose fluctuations
Q.120 Which of the following is a typical range for the arterial pulse pressure in adults?
10–20 mmHg
20–30 mmHg
30–50 mmHg
50–70 mmHg
Explanation - Normal pulse pressure ranges from about 30 to 50 mmHg.
Correct answer is: 30–50 mmHg
Q.121 Which of the following is a common method to reduce motion artifact in a wearable ECG sensor?
Use of a rigid mounting platform
Increase the sampling rate
Add a low‑pass filter
All of the above
Explanation - Stabilizing the sensor and filtering can mitigate motion artifact.
Correct answer is: All of the above
Q.122 Which of the following best explains the term 'aliasing' in signal sampling?
High frequency signals appear as lower frequencies
Low frequency signals are lost
Noise increases at high frequencies
Signal amplitude is reduced
Explanation - Aliasing occurs when a signal is undersampled, causing high‑frequency components to masquerade as low‑frequency ones.
Correct answer is: High frequency signals appear as lower frequencies
Q.123 Which of the following is a typical artifact in a pulse oximeter trace due to patient movement?
Baseline drift
Motion artifact
Mains interference
Signal saturation
Explanation - Movement alters the optical path and causes distortion in the signal.
Correct answer is: Motion artifact
Q.124 Which of the following sensors is used for measuring blood volume changes at the fingertip?
Photoplethysmograph
Blood pressure cuff
Capnograph
Thermistor
Explanation - PPG sensors measure blood volume changes in the microcirculation via optical methods.
Correct answer is: Photoplethysmograph
Q.125 What is the primary purpose of a 'signal conditioning' stage in a biomedical instrument?
Convert analog to digital
Filter, amplify, and shape the signal
Store data in memory
Display the signal on an LCD
Explanation - Signal conditioning prepares the raw sensor output for further processing.
Correct answer is: Filter, amplify, and shape the signal
Q.126 Which of the following is a key factor influencing the accuracy of an EEG?
Skin preparation
Reference electrode choice
Impedance matching
All of the above
Explanation - All factors affect signal quality in EEG acquisition.
Correct answer is: All of the above
Q.127 Which of the following is a typical measurement range for arterial oxygen saturation in a healthy adult?
70–80%
80–90%
90–95%
95–100%
Explanation - Healthy adults usually have SpO₂ values between 95% and 100%.
Correct answer is: 95–100%
Q.128 Which of the following is NOT a typical source of noise in ECG acquisition?
Mains interference
Muscle activity
Respiratory motion
Blood pressure measurement
Explanation - Blood pressure measurement does not introduce electrical noise to an ECG signal.
Correct answer is: Blood pressure measurement
Q.129 What is the main function of a photoplethysmographic sensor?
To measure electrical activity of the heart
To measure blood volume changes via optical methods
To measure blood pressure directly
To measure temperature changes
Explanation - PPG uses light absorption to infer changes in blood volume.
Correct answer is: To measure blood volume changes via optical methods
Q.130 Which of the following best describes a 'band‑stop filter' used in ECG signal processing?
Passes frequencies in a specific band
Attenuates frequencies in a specific band
Amplifies frequencies in a specific band
Reduces signal amplitude across all frequencies
Explanation - A band‑stop filter removes unwanted frequency components, such as mains interference.
Correct answer is: Attenuates frequencies in a specific band
Q.131 Which of the following is a typical measurement unit for blood pressure?
mmHg
kPa
Pa
All of the above
Explanation - Blood pressure is commonly expressed in millimeters of mercury.
Correct answer is: mmHg
Q.132 What does the term 'saturation index' refer to in pulse oximetry?
Ratio of oxygenated to total hemoglobin
Ratio of arterial to venous oxygenation
Ratio of light absorption at 660 nm to 940 nm
Ratio of heart rate to blood pressure
Explanation - Pulse oximeters compute SpO₂ by comparing absorption ratios at two wavelengths.
Correct answer is: Ratio of light absorption at 660 nm to 940 nm