A long solenoid is fabricated by closely winding a wire of radius 0.5 mm over a cylindrical nonmagnetic frame so that the successive turns nearly touch each other. What would be the magnetic field B at the centre of the solenoid if it carries a current of 5 A?

Options

A. `2pixx10^(-2) T`
B. `2pixx10^(-3) T`
C. `2pixx10^(-4) T`
D. `2pixx10^(-5) T`

Answer

B

Explanation

Number of turns in `1mm=1`
`n=1000 turns//m`
`B=mu_(0)ni=4pixx10^(-7)xx10^(3)xx5`
`=2pixx10^(-3)T`