Question

Assertion : Induced emf produced in a coil will be more when the magnetic flux linked with the coil is more. Reason (R): Induced emf produced is directly proportional to the magnetic flux.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Both Assertion (A) and Reason (R) are false.

Hint:

Always remember Faraday’s law: Induced emf depends on how fast flux changes, not how large the flux is.

Answer 1

The Correct Option is C

Concept: Faraday’s law of electromagnetic induction: \[ \mathcal{E} = -\frac{d\Phi}{dt} \] Where:

\( \mathcal{E} \) = induced emf
\( \Phi \) = magnetic flux
Important idea: Induced emf depends on rate of change of flux, not just flux.
Step 1: Analyze Assertion (A). If magnetic flux linked with a coil increases (and especially changes rapidly), induced emf increases. Thus, the assertion is generally considered true in practical context.
Step 2: Analyze Reason (R). The reason states: \[ \mathcal{E} \propto \Phi \] This is incorrect. From Faraday’s law: \[ \mathcal{E} \propto \frac{d\Phi}{dt} \] So emf depends on the rate of change of flux, not flux itself.
Step 3: Conclusion.

Assertion → True
Reason → False
Hence, option (C).