A solenoid 1.5 m long and 0.4 cm in diameter possesses 10 turns per cm length. A current of 5 A falls through it. The magnetic field at the axis inside the solenoid is

Options

A. `4p' 10^(-2) at`
B. `4p' 10^(-3) at`
C. `2p' 10^(-3) at`
D. `2p' 10^(-5) at`

Answer

C