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

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

Question 2

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

Question 3

A battery's capacity to deliver power is measured in

A. kWh

B. Ah

C. Wh

D. Vh

Question 4

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

Question 5

Conductance is expressed in terms of ___________

A. mho

B. mho/m

C. ohm/m

D. m/ohm

Question 6

Energy is defined as the ability to

A. produce heat

B. produce light

C. produce sound

D. All of the above

Question 7

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

Question 8

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

Question 9

Which of the following bulbs will have high resistance?

A. 220V, 60W

B. 220V,100W

C. 115V,60W

D. 115V,100 W

Question 10

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]

Question 11

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

Question 12

Ohm’s law is not applicable to ___________

A. dc circuits

B. high currents

C. small resistors

D. semi-conductors

Question 13

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

Question 14

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

Question 15

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

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

Question 17

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

Question 18

The rate at which work is performed is called

A. current

B. energy

C. power

D. voltage

Question 19

Resistivity of a wire depends on ___________

A. length of wire

B. cross section area

C. material

D. all of the mentioned

Question 20

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

Question 21

"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

Question 22

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

Question 23

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

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

Question 25

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

Question 26

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

Question 27

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

Question 28

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

Question 29

Give the SI unit of resistivity.

A. ohm/metre2

B. ohm metre2

C. ohm metre

D. ohm/metre

Question 30

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