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