A solid metal sphere of radius r is inside a metal concentric spherical shell of inner radius 2r and outer radius 3r. A charge is place on the
solid metal sphere and it is found that the potential at its surface is V1 (at r) and that the potential at the outer surface of the spherical
shell is Va (at 3r). In terms of V1 and V3, what is the potential at the inner surface of the metal shell (at 2r)?
A. 3V1/2 B. V3 C. V1 D. 2V3/2

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

laticia draws the diagram below to show earth’s magnetic field.

answer

the arrows to the right of earth should point up.