Electric Circuits Questions and Answers – The International System of Units, Voltage and Current, Power and Energy

This set of Electric Circuits Questions and Answers focuses on “The International System of Units, Voltage and Current, Power and Energy”.

1. Which of the following is a defined quantity?
a) Pressure
b) Polarity
c) Money
d) Length
View Answer

Answer: d
Explanation: The SI units are based on 7 defined quantities namely length, mass, time, electric current, thermodynamic temperature, amount of substance and also on the luminous intensity.

2. The basic unit for luminous intensity is
a) Ampere
b) Candela
c) Coulomb
d) Radian
View Answer

Answer: b
Explanation: The unit for luminous intensity is candela and its symbol is cd.

3. Which of the following is a correct relation?
a) Giga>Mega>Tera
b) Mega>Tera>Giga
c) Tera>Mega>Giga
d) Tera>Giga>Mega
View Answer

Answer: d
Explanation: Tera – 1012
Giga – 109
Mega – 106.
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4. Charge is
a) Unipolar
b) Bipolar
c) Tripolar
d) Non – Polar in nature
View Answer

Answer: b
Explanation: Charge is bipolar since it can be expressed in terms of positive and negative.

5. Separation of charge creates
a) Current
b) Voltage
c) Resistance
d) Friction
View Answer

Answer: b
Explanation: An electric force called voltage is created by separation of charge where as an electric fluid called current is created by motion of charge.
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6. The energy per unit charge is
a) Voltage
b) Power
c) Current
d) Work
View Answer

Answer: a
Explanation: Voltage, v=dw/dq and its SI unit is volt.

7. If charge q = 3t2 + 2 then current is given by
a) 6t + 2
b) 3t2
c) 6t
d) 3t2 + 2
View Answer

Answer: c
Explanation: I = dq/dt = d/dt(3t2 + 2) = 6t.
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8. If energy w = 200t2+ 99 et + 2 then calculate at 0.1 sec
a) 148.52
b) 149.41
c) 149.95
d) 148.39
View Answer

Answer: b
Explanation: p=dw/dt
=400t +99et
=400(0.1) + 99e(0.1)
=149.41

9. For the following circuit power is given by
The algebraic sign of power depends on movement of charge through drop & rise of voltage
a) –Vi
b) Vi
c) 0
d) 1
View Answer

Answer: a
Explanation: P = vi. The algebraic sign of power depends on movement of charge through the drop and rise of voltage.
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10. ‘Positive Power’ meaning ___________
a) Power is being delivered to circuit
b) Power is being extracted from circuit
c) No power supply
d) Input and output powers are equal
View Answer

Answer: a
Explanation: P > 0 means +ve Power
Being delivered
P < 0 means –ve Power
Being extracted.

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]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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