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Ohms Law MCQ Questions & Answers

Ohms Law MCQs : This section focuses on the "Ohms Law". These Multiple Choice Questions (MCQs) should be practiced to improve the Ohms Law skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.




Question 1

If the voltage across a fixed value of resistance is increased five times, what does the current do?

A. It increases by a factor of five.
B. It decreases by a factor of five.
C. It stays the same.
D. Not enough information

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Question 2

Identify the factor which does not depend on the resistance of a conductor.

A. Nature of material
B. Area of cross-section
C. Length
D. Viscosity

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Question 3

Conductance is expressed in terms of ___________

A. mho
B. mho/m
C. ohm/m
D. m/ohm

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Question 4

"Half-splitting" is

A. a means for nuclear fuel cells to produce electricity
B. a means of isolating a problem in a circuit
C. a means for reducing a high ac voltage to a low dc voltage
D. a means of limiting current in a circuit

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Question 5

Power supplies differ from batteries in that

A. power supply output voltages are ac and not dc
B. power supply voltages are not stable
C. power supplies are low-current devices
D. None of the above

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Question 6

Resistivity of a wire depends on ___________

A. length of wire
B. cross section area
C. material
D. all of the mentioned

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Question 7

Ohm's law is a relationship between

A. voltage, current, and time
B. power, current, and resistance
C. resistance, time, and current
D. voltage, current, and resistance

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Question 8

A damaged resistor

A. may appear burned
B. may have an increased resistance value
C. may be checked with an ohmmeter
D. All of the above

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Question 9

In a current-voltage relationship graph of a linear resistor, the slope of the graph will indicate ___________

A. conductance
B. resistance
C. resistivity
D. a constant

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Question 10

What is the reciprocal of resistivity of a material called? Give its unit.

A. Conductance, ohm-1
B. Conductivity, ohm-1 m-1
C. Conductance, ohm-1 m-1
D. Conductivity, ohm-1

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Question 11

What is the kilowatt-hour consumption of a 40 W lamp if it remains on for 1750 h?

A. 43.75
B. 70
C. 43750
D. 70000

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Question 12

The rate at which work is performed is called

A. current
B. energy
C. power
D. voltage

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Question 13

Which of the following bulbs will have high resistance?

A. 220V, 60W
B. 220V,100W
C. 115V,60W
D. 115V,100 W

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Question 14

Resistance of a wire is yΩ. The wire is stretched to triple its length, then the resistance becomes ___________

A. y/3
B. 3y
C. 6y
D. y/6

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Question 15

Consider a circuit with two unequal resistances in parallel, then ___________

A. large current flows in large resistor
B. current is same in both
C. potential difference across each is same
D. smaller resistance has smaller conductance

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Question 16

In which of the following cases is Ohm’s law not applicable?

A. Electrolytes
B. Arc lamps
C. Insulators
D. Vacuum ratio values

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Question 17

If the resistance in a circuit with constant voltage increases, the current will

A. increase
B. decrease
C. stay the same
D. Not enough information

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Question 18

Power supplies are regulated to prevent the output voltage from changing due to changes in the

A. line voltage
B. supply load
C. frequency
D. both line voltage and supply load

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Question 19

An electric current of 10 A is the same as ___________

A. 10 J/C
B. 10 V/C
C. 10C/sec
D. 10 W/sec

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Question 20

Give the SI unit of current density and its dimensional formula.

A. Am-2, [A1L-2]
B. Am2, [A1L2]
C. Am-1, [A1L-1]
D. Am1, [A1L1]

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Question 21

A battery's capacity to deliver power is measured in

A. kWh
B. Ah
C. Wh
D. Vh

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Question 22

If voltage across a resistance doubles

A. the current is halved
B. the resistance doubles
C. the current is unchanged
D. none of the above

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Question 23

Energy is defined as the ability to

A. produce heat
B. produce light
C. produce sound
D. All of the above

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Question 24

A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is V. If the diameter of wire is made d/4, then drift velocity becomes ___________

A. V/16
B. 16V
C. V
D. V/4

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Question 25

Ohm's law describes the mathematical relationship between

A. ohms, kilohms, and megohms
B. resistor size and resistor value
C. resistance, voltage, and current
D. none of the above

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Question 26

Give the SI unit of resistivity.

A. ohm/metre2
B. ohm metre2
C. ohm metre
D. ohm/metre

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Question 27

If current through a resistance is halved

A. the resistance is halved
B. the voltage is halved
C. the voltage doubles
D. none of the above

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Question 28

What is the reciprocal of resistance of a material called? Give its unit.

A. Conductance, ohm-1
B. Conductivity, ohm-1 m-1
C. Conductance, ohm-1 m-1
D. Conductivity, ohm-1

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Question 29

If doubling the voltage across a resistor doubles the current through the resistor then

A. the resistor value decreased
B. the resistor value did not change
C. the resistor value increased
D. it is impossible to determine the change in the resistor value

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Question 30

Ohm’s law is not applicable to ___________

A. dc circuits
B. high currents
C. small resistors
D. semi-conductors

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