You want to use the idea of electromagnetic induction to make the bulb in your s

Question

You want to use the idea of electromagnetic induction to make the bulb in your small flashlight glow; it glows when the potential difference across it is 1.5 V. You have a small bar magnet and a coil with 100 turns, each with area 2.9 × 104m2. The magnitude of the B  field at the front of the bar magnet's north pole is 3.6×102 T and reaches 0 T when it is about 4.0 cm away from the pole.

a) With what speed should you move the magnet to make the bulb light?

b) Can you make the bulb light? (yes/no/need more data)

Explanation / Answer

a)
Let dt is the time taken

induced emf = N*A*dB/dt

dt = N*A*dB/induced emf

= 100*2.9*10^-4*(3.6*10^-2 - 0)/1.5

= 6.96*10^-4 s

so, speed of the bar magnet = distane travelled/time taken

= 0.04/(6.96*10^-4)

= 57.5 m/s

b) No.

It is not possible to move the bar magnet wit that speed.

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