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NEETPhysicsElectromagnetic Induction

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The induced EMF between the centre and the rim of a metallic wheel rotating in a uniform magnetic field remains unchanged if the number of identical metallic spokes is increased. Reason (R): The metallic spokes act as identical sources of EMF connected in parallel between the centre and the rim. In

Options

  1. ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
  2. BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
  3. C(A) is correct but (R) is not correct
  4. D(A) is not correct but (R) is correct

Correct answer

A. Both (A) and (R) are correct and (R) is the correct explanation of (A)

Step-by-step solution

When a metallic wheel with spokes rotates in a uniform magnetic field, each spoke acts as a source of motional EMF of magnitude = 1 2 B r^2 . All the spokes are connected between the same two points: the centre of the wheel and its metallic rim. In an electrical circuit, when identical sources of EMF are connected in parallel, the equivalent EMF of the combination is equal to the EMF of a single source. Therefore, increasing the number of spokes does not change the net induced EMF between the centre and the rim. Bo

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