Question

A long solenoid is formed by winding 20 turns/cm. The current necessary to produce a magnetic field of 20 millitesla inside the solenoid will be approximately (\frac{{{\mu }_{0}}}{4\pi }={{10}^{-7}}\,tesla-metre/ampere)
[MP PMT 1994]
A) 8.0 A B) 4.0 A C) 2.0 A D) 1.0 A

Answer 1

B=u.NI

Usethis formula

Take 1 million tesla = 0.001 tesla

Answer 2

Answer:

8.0A

Explanation:

n=20cm

B=20mT

I=B/mu.n

20×10^-3/4π×10^-7×20×10^2

=8.0A