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`“Life is like riding a bicycle.  To keep your balance you must keep moving.”–Albert Einstein`

## Wednesday, December 30, 2009

### AP Physics C – Electromagnetism – A Free Response Practice Question

You can access all posts involving magnetic fields and electromagnetic induction on this blog by trying a search using the search box at the top of this page or by clicking on the labels ‘magnetic field’ and ‘electromagnetic induction’ below this post. Today I give you a free response practice question on electromagnetism. This question is for AP Physics C aspirants: A rectangular wire loop of length and breadth b having negligible resistance is arranged in the plane of an infinitely long straight vertical wire as shown, with the longer sides parallel to the wire. The wire loop contains a capacitor of capacitance C. A steady current ‘I’ flows upwards through the straight wire. Now answer the following questions:

(a) Calculate the magnetic flux through the wire loop.

(b) The loop is rotated through 180º about a central axis (fig) which is parallel to the straight wire. If the time taken for this rotation is t, determine the magnitude of the emf induced in the loop.

(c) The loop is kept stationary and instead of the steady current I, a current ‘i varying with time t as i = Im sin ωt (where Im and ω are constants) is passed through the straight wire. Calculate the maximum value of the emf induced in the wire loop.

(d) Determine the maximum current induced in the wire loop under the conditions mentioned in part (c) above.

Try to answer this question. You can take 15 minutes for answering it and can score up to 15 points for the right answer. I’ll be back soon with a model answer for your benefit.