MCQ Motional emf, Class 12 Physics

1. There will be total 10 MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying

1. The magnetic flux passing normally through a coil is ø = 20 cos πt + t² + 50 + 25m Wb What will be the induced emf at t = 1s?

100 π mV

52 mV

72m V

(100 π + 50) mV

Question 1 of 10

2. A copper rod moves parallel to the horizontal direction. The induced emf developed across its ends due earth's magnetic field will be maximum at the

latitude 60°

latitude 30°

equator

poles

Question 2 of 10

3. The magnetic flux through a surface varies with time as follows:
= 12t² + 7t + 3
here,   is in milliweber and t is in seconds.
What will be the induced emf at t = 5s?

338 mV

127 mV

105 mV

None of the above

Question 3 of 10

4. In Faraday's experiment if the magnet is moved towards the coil, it results in ____________ in magnetic field B at any point on the wire loop. The _________ shows deflection. Thus emf is induced by changing B.

Decrease, galvanometer

Increase, ammeter

Increase, galvanometer

Decrease, ammeter

Question 4 of 10

5. What is the value of induced e.m.f if a wire is moved between the gap of two poles of a magnetin in 1 s and magnetic flux between the poles is 6 x 10^-3 Wb?

0.6 mV

6 mV

66 mV

60 mV

Question 5 of 10

6. Two similar circular co-axial loops carry equal current in the same direction. If the loops be brought nearer, the currents in them will

Change direction

Decrease

Increase

Remain same

Question 6 of 10

7. When a wire loop is rotated in a magnetic field, the direction of induced emf changes once in each

2 revolutions

1 revolution

1/2 revolution

12 revolution

Question 7 of 10

8. The induced e.m.f in a coil is given by . Calculate the number of rotations the coil makes per second.

100 rps

5 rps

15 rps

50 rps

Question 8 of 10

9. The motional emf produced across a wire moving through a magnetic field does not depend on its:

orientation

velocity

diameter

length

Question 9 of 10

10. If we keep two similar loops made up of copper and constantan in a magnetic field for same amount of time, in which loop the induced e.m.f will be greater.

Constantan Loop

E.m.f won't be induced in any of the loops

Copper Loop

Equal in both the loops

Question 10 of 10

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