question_answer 13)

It is desired to measure the magnitude of field between the poles of a powerful loud speaker magnet. A small flat search coil of area with 25 closely would turns, is positioned normal to the field direction, and then quickly snatched out of the field region. Equivalently, one can give it a quick turn to bring its plane parallel to the field direction. The total charge flown in the coil (measured by a ballistic galvanometer connected to coil) is 7.5 mC. The combined resistance of he coil and the galvanometer is . Estimate the field strength of magnet.  

Answer:

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