A Cylindrical Region of Radius R Contains a Uniform Magnetic

Multiple Choice

A cylindrical region of radius R contains a uniform magnetic field parallel to its axis. The field is zero outside the cylinder. If the magnitude of the field is changing at the rate dB/dt, the electric field induced at a point 2R from the cylinder axis is:

A) zero
B) 2R dB /dt
C) R dB /dt
D) (R/2) dB /dt
E) (R/4) dB /dt