MCQs on Electromotive Force (EMF)

MCQs on Electromotive Force (EMF)

Q1. The flux used in the equation for the calculation of induced emf in a transformer is in its

1. RMS value
2. Average value
3. Maximum value
4. Twice that of the maximum value

Answer: (c) Maximum value

Q2: What should be the value of primary to the secondary ratio for  a transformer to be an isolation transformer?

1. Equal to one
2. Less than one
3. More than one
4. Equal to 0.5

Answer: (a) Equal to one

Q3. The average emf induced per turn in a transformer is given by

1. 1.11f Φ_m
2. 0.5f Φ_m
3. 4f Φ_m
4. 8f Φ_m

Answer : (c) 4f Φ_m

Q4. Who introduced the right-hand rule for determining the direction of the induced EMF?

1. Fleming
2. Lenz
3. Maxwell
4. Faraday

Answer: (a) Fleming

Q5. Whenever there is a change in magnetic flux with respect to an electric conductor or a coil, an EMF is induced in the conductor is Faraday’s

1. first law
2. third law
3. second law
4. fourth law

Answer: (a) first law

Q6. Power of battery having emf E₁=20V is

1. 44.2 Watt
2. 30.8 Watt
3. 13.4 Watt
4. 20 Watt

(c) Answer: (a) 44.2 Watt

Q7: In which device is the principle of statically induced emf used?

1. Transformer
2. Motor
3. Generator
4. Battery

Answer: (a)Transformer

Q8: Statically induced emf’s magnitude depends on the

1. Rate of change of flux
2. Coil resistance
3. Flux magnitude
4. None of these

Answer: (a) Rate of change of flux

Q9: Which is the property of a coil by which a counter emf is induced when the current through the coil changes?

1. Self-inductance
2. Mutual inductance
3. Capacitance
4. None of these

Answer: (a) Self-inductance

Q10: Principle of dynamically induced emf is used in a

1. Choke
2. Transformer
3. Generator
4. Thermo-couple

Answer: (c) Generator