Question

The length of a solenoid is $0.1m$ and its diameter is very small. A wire is wound over in two layers. The number of turns in the inner layer is $50$ and that on the outer layer is $40$. The strength of current flowing in two layers in the same direction is $3$ ampere. The magnetic induction in the middle of the solenoid will be

• A. $3.4\times 10^{-3}T$
• B. $3.4\times 10^{-3}gauss$
• C. $3.4\times 10^{3}T$
• D. $3.4\times 10^{3}gauss$

Answer 1

Answer: (A)

$B=\frac{{\mu }_{0}i}{L}(N_1+N_2)$