Question

A tightly wound coil of 10cm carrying a current of 1A.What is magnetic field at centre of coil

Answer 1

Given:

$N=1000$

$I=1\:\rm A$

$l=0.1\:\rm m$

The magnetic field inside a solenoid

$$B=\mu_0 NI/l$$ $$B=4\pi*10^{-7}*1000*1/0.1=0.013\:\rm T$$