Free SCFHS Biomedical Engineering & Medical Devices mock test

Biomedical Engineering & Medical Devices sample questions with answers

10 more original exam-style Biomedical Engineering & Medical Devices questions, worked in full. They are not real or recalled exam questions, and none of them is in the mock above or on the bank page, so sit the mock first if you have not.

1. Question 1 · Advanced Electronics and Electricity

   A diagnostic ECG has useful content up to 150 Hz and is digitised. Which sampling rate is the minimum that satisfies the Nyquist criterion?

   1. AMore than 300 samples per second
   2. B150 samples per second
   3. CMore than 75 samples per second
   4. D100 samples per second
   Show answer and explanation

   Correct answer: A. More than 300 samples per second

   The sampling rate must exceed twice the highest signal frequency, so above 300 Hz. Sampling at 150 or 100 Hz causes aliasing, and 75 Hz is half the bandwidth rather than double it.

   Reference: Webster (ed.), Medical Instrumentation: Application and Design, 4th ed., 2010

2. Question 2 · Biomedical Equipment Technology

   The daily Bowie-Dick test on a pre-vacuum steam sterilizer shows an uneven colour change, with an unchanged patch in the centre of the sheet. What is the most likely cause?

   1. AThe chamber exceeded 134 degrees Celsius and stayed hot for too long a hold time
   2. BThe biological indicator vial was placed upside down inside the test pack
   3. CThe detergent used on the previous load was too alkaline and left a residue
   4. DIncomplete air removal, for example from a door gasket or vacuum leak
   Show answer and explanation

   Correct answer: D. Incomplete air removal, for example from a door gasket or vacuum leak

   A Bowie-Dick sheet tests air removal and steam penetration. A centre patch that did not change means trapped air, usually from a leak or a failing vacuum. Overheating would not leave a patch unchanged, and the biological indicator and detergent are not part of this test.

   Reference: AAMI ST79:2017, Comprehensive guide to steam sterilization

3. Question 3 · Medical Informatics

   A networked infusion pump runs an unsupported operating system and the vendor cannot supply a patch. Which action best manages the risk?

   1. ADisable the pump alarms so that network traffic does not interrupt delivery
   2. BConnect it directly to the main hospital network so it can receive updates
   3. CLeave it unchanged because clinical devices are exempt from cybersecurity risk
   4. DPlace it on an isolated network segment with restricted firewall rules and document the residual risk
   Show answer and explanation

   Correct answer: D. Place it on an isolated network segment with restricted firewall rules and document the residual risk

   Where a device cannot be patched, network segmentation and access control reduce exposure, and the remaining risk is recorded under a risk management process. Disabling alarms harms patients, open connection raises risk, and no device is exempt.

   Reference: IEC 80001-1:2021, Application of risk management for IT networks incorporating medical devices

4. Question 4 · Chemistry

   A flexible endoscope is being reprocessed. Why must manual cleaning with enzymatic detergent come before high-level disinfection?

   1. ADetergent sterilises the channels, so disinfection afterwards is a final rinse step
   2. BOrganic soil shelters microorganisms from the disinfectant and weakens its action
   3. CEnzymes raise the pH enough to kill spores that remain inside the lumen of the scope
   4. DSoil makes the disinfectant too concentrated for the scope material to tolerate safely
   Show answer and explanation

   Correct answer: B. Organic soil shelters microorganisms from the disinfectant and weakens its action

   Residual blood and tissue protect organisms and consume or neutralise chemical disinfectants, so cleaning must remove them first. Detergent does not sterilise, enzymes do not kill spores through pH, and soil dilutes rather than concentrates the disinfectant.

   Reference: CDC, Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008

5. Question 5 · Biomedical Equipment Technology

   How do the cut and coagulation modes of an electrosurgical unit differ?

   1. ACut uses an interrupted waveform, and coagulation uses a continuous low-voltage one
   2. BBoth use the same waveform at different foot pedal pressures
   3. CCut uses direct current, and coagulation uses alternating current
   4. DCut is continuous and low voltage, coagulation is pulsed and higher voltage
   Show answer and explanation

   Correct answer: D. Cut is continuous and low voltage, coagulation is pulsed and higher voltage

   A continuous waveform concentrates heat to vaporise tissue for cutting, while a pulsed, higher-voltage waveform gives time for cooling and produces coagulation. Reversing the modes is wrong, and the waveforms are set by the generator, not by pedal pressure. Both modes use high-frequency alternating current.

   Reference: Webster, Medical Instrumentation: Application and Design, 4th ed. (2010)

6. Question 6 · Advanced Electronics and Electricity

   A step-down transformer has 1150 primary turns and changes 230 V to 12 V. How many secondary turns does it have?

   1. A60
   2. B30
   3. C120
   4. D600
   Show answer and explanation

   Correct answer: A. 60

   The voltage ratio equals the turns ratio, so the secondary turns are 1150 x 12 / 230 = 60. The values 30 and 120 are half and double that figure, and 600 comes from an incorrect ratio.

   Reference: Sedra and Smith, Microelectronic Circuits, 7th ed. (2014)

7. Question 7 · Mathematics

   A blood pressure of 120 mmHg is converted to kilopascals. Which value is closest?

   1. A12 kPa
   2. B16 kPa
   3. C90 kPa
   4. D160 kPa
   Show answer and explanation

   Correct answer: B. 16 kPa

   One mmHg is about 0.133 kPa, so 120 mmHg is about 16 kPa. The value 12 kPa is about 90 mmHg. The values 90 and 160 come from using the wrong factor.

   Reference: NIST Guide for the Use of the International System of Units (2008)

8. Question 8 · Medical Informatics

   Which backup arrangement follows the 3-2-1 rule for clinical data?

   1. AThree copies on one server in the same room
   2. BTwo copies on one disk, with a tape beside the server
   3. CThree copies on two media, one off site
   4. DOne copy on three media kept on site
   Show answer and explanation

   Correct answer: C. Three copies on two media, one off site

   The 3-2-1 rule keeps three copies, on two different media, with one copy away from the site so that a single event cannot destroy all of them. Copies on one server or in one room share the same risk.

   Reference: US-CERT/CISA Data Backup Options (2012)

9. Question 9 · Practical Experience

   When calibrating a device, which accuracy ratio between the reference standard and the device under test is generally accepted as a minimum?

   1. AA ratio of at least 4 to 1
   2. B1 to 1, as both are calibrated
   3. C2 to 1 for general devices
   4. D10 to 1 for electrical safety tests
   Show answer and explanation

   Correct answer: A. A ratio of at least 4 to 1

   A reference that is at least four times more accurate than the device under test is the traditional test accuracy ratio and keeps the reference error from masking the device error. A 1 to 1 ratio leaves no margin, and a ratio of 2 to 1 is weaker than the usual rule.

   Reference: MIL-STD-45662A Calibration Systems Requirements (1988); ANSI/NCSL Z540.3 (2006)

10. Question 10 · Patient Safety, Electrical Safety and Hazards

    In MRI safety zoning, which zone contains the scanner magnet?

    1. AZone I
    2. BZone II
    3. CZone III
    4. DZone IV
    Show answer and explanation

    Correct answer: D. Zone IV

    Zone IV is the magnet room, where the field is always on and access is supervised. Zone I is the public area, Zone II is reception and screening, and Zone III is the restricted control area.

    Reference: ACR Manual on MR Safety (2020)