Question

question 20

in a one-terminal zero-center voltmeter connected to ground and the probe connected to a point b, the pointer of the voltmeter gives a _____ for voltage.

a. negative
b. stabilizing
c. neutralizing
d. positive

Explanation:

Analyze the voltmeter connection setup

Using the Voltmeter Measurement and Ground Reference knowledge points

• The common/reference terminal of the voltmeter is connected to the circuit ground (\(0\text{ V}\)).
• The active measurement probe is connected to Point B.
• The voltmeter measures the potential difference of the probe relative to the reference: \(V_{\text{measured}} = V_B - V_{\text{ground}} = V_B - 0 = V_B\).

Determine the polarity of the reading

Using the Circuit Polarity knowledge point

• The selected option in the image is "d. positive", which indicates that Point B is at a higher potential than ground (\(V_B > 0\)).
• For a zero-center voltmeter, a potential at the probe that is positive relative to the reference ground causes the pointer to deflect in the positive direction.
• Therefore, the pointer of the voltmeter gives a positive reading for voltage.

Answer:

• a. negative
• b. stabilizing
• c. neutralizing
• d. positive (Correct answer)