A small flat search coils of area 4 cm2 with 20 closely wound turns is positioned normal to the field direction and then quickly snatched out of the field region. The total charge flowing in the coil (measured by a ballastic galvanometer connected to the coil) is 7.5 mC. The resistance of teh coil and galvanometer is 0.8 Ω. The field strength of the magnet is