CBET General Practice 5 — Questions and Answers
Question 1: When using a multimeter to measure AC voltage on a 120V circuit, the technician should set the range to:
- The lowest range below 120V for best accuracy
- A range equal to or above 120V to prevent meter damage (Correct answer)
- DC voltage at 200V
- Resistance mode to check the circuit first
Correct answer: A range equal to or above 120V to prevent meter damage
Always select a range at or above the expected voltage to prevent damage to the meter and ensure safe, accurate measurement.
Question 2: A hospital laboratory centrifuge vibrates excessively during operation. The MOST likely cause is:
- Motor bearing wear causing rotor imbalance
- An unbalanced load due to improperly paired or misplaced samples (Correct answer)
- Excessive ambient temperature in the lab
- A failed tachometer sensor
Correct answer: An unbalanced load due to improperly paired or misplaced samples
Centrifuges must have balanced loads; unequal or improperly positioned samples create centrifugal force imbalance causing severe vibration.
Question 3: Which type of radiation is MOST effectively stopped by a thin sheet of aluminum foil?
- Gamma rays
- X-rays
- Beta particles (Correct answer)
- Alpha particles
Correct answer: Beta particles
Beta particles (electrons) have moderate penetration and are effectively shielded by a few millimeters of aluminum, unlike alpha (paper stops it) or gamma (requires dense shielding).
Question 4: A technician completing a work order should document which of the following to satisfy Joint Commission traceability requirements?
- Only the parts replaced and their cost
- Device identification, service performed, test results, technician ID, and date (Correct answer)
- The patient census count at time of service
- Only failures found, not routine PM results
Correct answer: Device identification, service performed, test results, technician ID, and date
Joint Commission requires complete service records including device ID, work performed, test results, technician identification, and the service date for full traceability.
Question 5: The output impedance of a device should ideally be low because:
- It increases the device's power consumption
- It minimizes signal voltage drop when driving a load (Correct answer)
- It prevents electromagnetic interference
- It increases current draw from the power supply
Correct answer: It minimizes signal voltage drop when driving a load
Low output impedance ensures minimal voltage drop across the source impedance when current flows, maintaining signal integrity to the load.
Question 6: Which sterilization method is MOST appropriate for heat-sensitive flexible endoscopes?
- Steam autoclave at 134°C
- Ethylene oxide (EtO) gas sterilization (Correct answer)
- Dry heat oven at 160°C
- UV light irradiation
Correct answer: Ethylene oxide (EtO) gas sterilization
Ethylene oxide gas sterilizes at low temperatures (37–63°C), making it suitable for heat-sensitive devices like flexible endoscopes that would be damaged by steam or dry heat.
Question 7: In an op-amp configured as an inverting amplifier with Rf = 100 kΩ and Rin = 10 kΩ, the voltage gain is:
- +10
- -10 (Correct answer)
- +0.1
- -0.1
Correct answer: -10
The inverting amplifier gain is -Rf/Rin = -100kΩ/10kΩ = -10, where the negative sign indicates phase inversion.
CBET General Practice 5
When using a multimeter to measure AC voltage on a 120V circuit, the technician should set the range to: