Find charge inner/hollow sphere

[g98]

Homework Statement

A hollow conducting sphere with an inner radius of 5 cm and an outer radius of 6 cm contains a smaller sphere of radius 3 cm, located symmetrically inside the hollow sphere. The electric field strength at 4 cm from the center is measured to be 2400 N/C pointing inward. The electric field strength at 20 cm from the center is determined at 300 N/C pointing away from the spheres. Use this information to determine: a. the charge on the inner sphere b. the charge on the hollow sphere

Homework Equations

The Attempt at a Solution

I know I have to use the gauss's law but I am not quite sure how to do it

 

[ehild]

Homework Statement

A hollow conducting sphere with an inner radius of 5 cm and an outer radius of 6 cm contains a smaller sphere of radius 3 cm, located symmetrically inside the hollow sphere. The electric field strength at 4 cm from the center is measured to be 2400 N/C pointing inward. The electric field strength at 20 cm from the center is determined at 300 N/C pointing away from the spheres. Use this information to determine: a. the charge on the inner sphere b. the charge on the hollow sphere

Homework Equations

The Attempt at a Solution

I know I have to use the gauss's law but I am not quite sure how to do it

You have to show some attempt at solving the problem. What does Gauss' Law state?

 

[PKM]

Consider first a gaussian surface of radius $r$ cm with $3\lt r\lt 5$, and try to apply gauss's law. Also note that if $Q$ be the charge of the inner sphere, the inner surface of the spherical shell must have charge $-Q$.