Correct Answer:
C. By detecting changes in the capacitance between the probe and the tank wall as the liquid level rises or falls, which is then converted into an electrical signal.
Explanation:
- A. Incorrect: Capacitance probes do not generate or use magnetic fields to measure liquid levels.
- B. Incorrect: Capacitance probes measure changes in capacitance, not resistance, to determine liquid levels.
- C. Correct: A capacitance probe works by detecting changes in the capacitance between the probe and the tank wall. As the liquid level changes, the dielectric constant between the probe and the wall changes, altering the capacitance. This change is then converted into an electrical signal that can be used to measure the liquid level.
- D. Incorrect: This describes the operation of an ultrasonic level sensor, not a capacitance probe.
Correct Answer:
C. By detecting changes in the capacitance between the probe and the tank wall as the liquid level rises or falls, which is then converted into an electrical signal.
Explanation:
- A. Incorrect: Capacitance probes do not generate or use magnetic fields to measure liquid levels.
- B. Incorrect: Capacitance probes measure changes in capacitance, not resistance, to determine liquid levels.
- C. Correct: A capacitance probe works by detecting changes in the capacitance between the probe and the tank wall. As the liquid level changes, the dielectric constant between the probe and the wall changes, altering the capacitance. This change is then converted into an electrical signal that can be used to measure the liquid level.
- D. Incorrect: This describes the operation of an ultrasonic level sensor, not a capacitance probe.