- AA and C only
- BC and D only
- CB and D only
- DB and C only
View written solutionFree
Correct answer: B
-
Use Faraday’s law
The induced emf in a coil is produced when the magnetic flux through the coil changes: where magnetic flux is for a coil in a uniform magnetic field.
So emf is induced if any of the following changes with time:
- magnetic field
- area
- angle
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Check each statement
A. Moving the coil with uniform speed inside uniform magnetic field
If the coil moves as a whole in a uniform magnetic field, then , , and remain unchanged. Hence flux does not change. So no induced emf.
Therefore, A is false.
B. Moving the coil with non-uniform speed inside uniform magnetic field
Even if the speed is non-uniform, as long as the coil moves bodily inside a uniform magnetic field without changing area or orientation, the flux remains constant.
So again, Hence no induced emf.
Therefore, B is false.
C. Rotating the coil inside the uniform magnetic field
On rotating the coil, the angle between the field and the area vector changes with time. Therefore flux changes: Hence induced emf is produced.
Therefore, C is true.
D. Changing the area of the coil inside the uniform magnetic field
If the area changes with time, then flux changes: Hence induced emf is produced.
Therefore, D is true.
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Conclusion
The correct statements are:
-
Match with options
- Option A: A and C only — incorrect
- Option B: C and D only — correct
- Option C: B and D only — incorrect
- Option D: B and C only — incorrect
Therefore, the correct answer is Option B.
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