Motional EMF
The arm PQ of a rectangular conductor is moving from x = 0 to x = 2b outwards and then inwards from x = 2b to x = 0 as shown in the figure. A uniform magnetic field perpendicular to the plane is acting from x = 0 to x = b. Identify the graph showing the variation of different quantities with distance.

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Answer: (b)
- Flux: rises linearly from to (area in field grows), stays constant from to and back to , then falls to zero. This is graph A.
- EMF : constant while going out ( to ), zero outside the field, constant with opposite sign while coming back. This is graph B.
- Power : same positive value in both field stretches, zero elsewhere. This is graph C.
- So the answer is (b) A-Flux, B-EMF, C-Power dissipated.