Question

A long solenoid of $N$ turns has a self-inductance $L$ and area of cross-section $A$. When a current $i$ flows through the solenoid, the magnetic field inside it has magnitude $B$, The current is equal to

• A. $\frac{BAN}{L}$
• B. $BANL$
• C. $\frac{BN}{AL}$
• D. $\frac{B}{ANL}$

Answer 1

Answer: (A)

$N\varphi =LI$
$NBA=LI$
$I=\frac{NBA}{L}$