EMF in Rotating Coil – Rankers Physics

Faraday's Law of Electromagnetic Induction: Practice Problem & Solution

Assertion (A): When a coil is rotated in a uniform magnetic field about an axis perpendicular to the field, emf is induced in it which is maximum for the orientation of coil in which magnetic flux through the coil is zero. Reason (R): In an electric generator, electrical energy is generated by rotating a coil in a magnetic field.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Faraday's Law of Electromagnetic Induction. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true because \( \epsilon = BA\omega sin(\omega t) \), which is max when \( \Phi_B = BA cos(\omega t) = 0 \). Reason (R) is also true, describing generators. However, (R) is an application and doesn't explain the condition for maximum emf in (A).

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