Question

A 33 cm diameter coil consists of 19 turns of cylindrical copper wire 2.8 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 9.50

Answer 1

The resistance of the wire is

              R = ?L/(?r^2)

Here ? = 1.72 x 10-8 ?/m

         L = (19)(?d)

             = (19)(?(2.80x 10^-3 m))

             = 0.167 m

         r = (2.80 x 10^-3 m)/2

           = 1.40  x 10^-3 m

        R = ?L/(?r^2)

            = ( 1.72 x 10-8 ?/m) (0.167 m)/(?( 1.40  x 10^-3 m)^2)

            = 4.66x 10^-4 ?

The formula for the induced emf is

         e =- NA (?B/?t)

           =- (19)(?(0.165m)^2)(0.0095 T/s)

           = - 0.0146 V

So the magnitude of the induced current is

             I= e/R

               =(0.0146 V)/( 4.66x 10^-4 ?)

               = 31.34 A