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 `2 cm^2` with 25 closely wound turns, is positioned normal to the field direction, and then quickly snatched out of the field region. Equivalently, one can give it a quick `90^@` 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 the coil and the galvanometer is `0.50 Omega`. Estimate the field strength of magnet.