# Electric Circuits Questions and Answers – Measuring Voltage and Current

This set of Electric Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Measuring Voltage and Current”.

1. ____________ helps in current measurement by placing it in ____________ with the circuit element.
a) Voltameter, Parallel
b) Ammeter, series
c) Voltmeter, series
d) Ammeter, parallel

Explanation: In series, current is same. So Ammeter is placed in series and is used to measure current.

2. An ideal voltmeter has ___________ equivalent resistance and ideal ammeter has ___________ equivalent resistance.
a) Unity, Unity
b) Zero, infinite
c) Infinite, Zero
d) Zero, Zero

Explanation: An ideal voltmeter has Infinite equivalent resistance and ideal ammeter has zero equivalent resistance.

3. Continuous voltages (or) current signals are measured using
a) Tachometers
b) Sonometers
c) Analog meters
d) Digital meters

Explanation: Digital meters are used to measure current (or) voltage signals at discrete points in time known as sampling times.

4. Digital meters are preferable than analog meters.
a) True
b) False

Explanation: Features like easy connection, Introduction of less resistance into the circuit to which they all connected and also due to read out mechanism digital meter are preferred.

5. A 20mv, 1mA d’Arsonval movement is used in an ammeter whose full-scale reading is 10 mA. Determine RA.
a) 2.222Ω
b) 6.667Ω
c) 5.92Ω
d) 3.333Ω

Explanation:

1 mA flowing through coil implies that 9mA must be diverted through RA.
V = ir
20 * 10-3 = 9 * 10-3 RA
RA= 2.222Ω.
Note: Join free Sanfoundry classes at Telegram or Youtube

6. A 25mv, 2mA d’Arsonval movement is to be used in voltmeter whose full scale reading is 100v. The resistance inserted by 100v meter into circuit is ___________
a) 1 * 105
b) 1 * 106
c) 1 * 104
d) 1 * 103

Explanation: v = iR
R = v/i
= 100/1mA
= 100,000Ω.

7. An ideal voltmeter functions as __________ circuit.
a) A short
b) An open
c) A power
d) An infinite

Explanation: An ideal voltmeter offers an infinite equivalent resistance. So acts as an open circuit.

8. An ideal ammeter functions as __________ circuit.
a) A short
b) An open
c) A power
d) An infinite

Explanation: An ideal ammeter offers a zero equivalent resistance. So acts a short circuit.

9. A 100mv, 5mA d’Arsonval movement is to be used in an ammeter whose full-scale reading is 1A. Calculate RA.
a) 0.7 ohms
b) 0.5 ohms
c) 0.1 ohms
d) 0.2 ohms

Explanation: 5mA is flowing through the coil which implies 995mA are diverted through RA.
V = iR
= 100 * 10-3
= 995 * 10-3 RA
RA = 0.100Ω.

10. A 122mv, 12mA d’Arsonval movement is to be used in voltmeter whose full scale reading is 120v. The resistance inserted by 120v _____________
a) 1200Ω
b) 12000Ω
c) 1000Ω
d) 10,000Ω

Explanation: R =120/12 * 10-3
= 10,000Ω.

Sanfoundry Global Education & Learning Series – Electric Circuits.

To practice all areas of Electric Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]