CBSE Class 12 · 2013 · Electromagnetic InductionVery Short Answer

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The motion of a copper plate is damped when it is allowed to oscillate between the two poles of a magnet. If slots are cut in the plate, how will the damping be affected?

Answer: The damping decreases (becomes weaker).

Solution

The damping is caused by eddy currents induced in the plate as the flux through it changes; these currents dissipate the mechanical energy as heat.
Cutting slots breaks up the large conducting loops, lengthening the available paths and raising their resistance.
The eddy currents are therefore reduced, less energy is dissipated, and

the damping becomes weaker

CBSE Class 12 Board · 2013 · Subjective

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