A long solenoid has 800 turns per metre length of solenoid. A current of 1.6 A flows through it. The magnetic induction at the end of the solenoid on its axis is
Answer & explanation
Correct answer: option 2
$ B = \frac{\mu_0 nI}{2}$
$n = 800$
$I = 1.6 $
$\Rightarrow B = \frac{4\pi\times 10^{-7}\times 800 \times 1.6}{2} = 8 \times 10^{-4}T$