Basic Electrical Engineering Questions and Answers – Electromagnetic Induction

«
»

This set of Basic Electrical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Electromagnetic Induction”.

1. An E.M.F. can be induced by _________
a) Change in the magnetic field only
b) Change in the area of cross section only
c) Change in angle between magnetic field and area only
d) Change in the magnetic field, area or angle between them
View Answer

Answer: d
Explanation: emf=-dϕ/dt. We know ϕ flux is the dot product of magnetic field vector and area vector.
ϕ=BAcos(θ), hence if either of the three, that is, magnetic field, area or angle changes, the emf will change, flux changes due to which emf can be induced.
advertisement

2. What happens to the current in a coil while accelerating a magnet inside it?
a) Increases
b) Decreases
c) Remains constant
d) Reverses
View Answer

Answer: a
Explanation: A change in the magnetic field induces an emf. When there is an emf, there has to be current. Hence, when the magnet is moved inside a coil, the current in it increases.

3. What is the consequence of motor effect?
a) Current
b) Voltage
c) Electromagnetic induction
d) EMF
View Answer

Answer: c
Explanation: Motor effect is when a current carrying conductor in a magnetic field experiences a force, hence its consequence is electromagnetic induction.
advertisement
advertisement

4. The total number of magnetic field lines passing through an area is termed as?
a) Voltage
b) EMF
c) Magnetic flux
d) Magnetic flux density
View Answer

Answer: c
Explanation: Number of magnetic field lines passing through an area is magnetic flux.

5. The formula for induced emf if magnetic field, length and velocity of conductor all are mutually perpendicular is __________
a) emf=B2l
b) emf=Bil
c) emf=Blv
d) emf=B2v
View Answer

Answer: c
Explanation: The formula for induced emf is emf=Blv, where B is the magnetic field, l is the length of the conductor and v is the velocity with which it is moving in the magnetic field and all three quantities are mutually perpendicular to each other.
advertisement

6. If a conductor 0.2m long moves with a velocity of 0.3m/s in a magnetic field of 5T, calculate the emf induced if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 0.3V
b) 0.03V
c) 30V
d) 3V
View Answer

Answer: a
Explanation: The formula for induced emf is: emf=Blv if B,l,v are perpendicular to each other. Substituting the values of B, l and v from the question, we get emf=0.3V.

7. Find the length of a conductor which is moving with a velocity 0.4m/s in a magnetic field of 8T, inducing an emf of 20V if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 50m
b) 5m
c) 6.25m
d) 0.5m
View Answer

Answer: c
Explanation: The formula for induced emf is: emf=Blv if B, l, v are perpendicular to each other. Substituting the values of B, emf and v from the question, we get l=6.25m.
advertisement

8. Find the strength of the magnetic field in a conductor 0.5m long moving with a velocity of 10m/s, inducing an emf of 20V if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
a) 1T
b) 2T
c) 3T
d) 4T
View Answer

Answer: d
Explanation: The formula for induced emf is: emf=Blv if B, l, v are perpendicular to each other. Substituting the values of l, emf and v from the question, we get B=4T.

9. What does emf stand for?
a) Electronic magnetic force
b) Electromotive force
c) Electromagnetic force
d) Electromated force
View Answer

Answer: b
Explanation: Emf stands for electromotive force. It is the voltage developed by any source of electrical energy.
advertisement

10. What is emf?
a) Force
b) Voltage
c) Current
d) Flux
View Answer

Answer: b
Explanation: Electromotive force is not actually a force. It is basically a voltage. It is the voltage developed by any source of electrical energy.

Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.

To practice all areas of Basic Electrical Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

advertisement
advertisement
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter