In the figure a very thin spherical plastic shell of radius

In the figure a very thin spherical plastic shell of radius 15 cm carries a uniformly-distributed negative charge of -5 nC (-5e-9 C) on its outer surface. An uncharged solid metal block is placed nearby. The block is 10 cm thick, and the left surface of the block is 10 cm away from the surface of the sphere. Calculate the magnitude of fiblock the electric field at the center of the metal block, due only to the charges on the block itself. (Hint: make sure you use the appropriate distance in your calculation.) I & block I = X N/C What is the magnitude of the net electric field at the center of the metal block?

Solution

a)

The magnitude of the electric field at the center of the metal block is

E_block=KQ/r²

where r=distance from center of sphere to the center of the block

r =0.15+0.1+(0.1/2)=0.3 m

E_block=(9*10⁹)(5*10^-9)/0.3²

E_block=500 N/C

b)

The net electric at the center of the metal block is zero.s

E_net=0

since the metal block is kept near the sphere a positive charge is induced on left side of the block and negative charge on right side ,making the net charge zero.