Question

In a long straight solenoid with cross-sectional radius $a$ and number of turns per unit length, $n$, the current varies with the rate $IA/s$. The magnitude of the induced current field strength as a function of distance $r$ from the solenoid axis is

• A. $\frac{1}{2}\frac{nI{a}^2}{{\mu }_{0}r}$
• B. $\frac{1}{2}\frac{I{a}^2}{{\mu }_{0}r}$
• C. $\frac{nI{a}^2}{{\mu }_{0}r}$
• D. $\frac{1}{2}\frac{{\mu }_{0}nI{a}^2}{r}$

Answer 1

Answer: (D)

$\frac{1}{2}\frac{{\mu }_{0}nI{a}^2}{r}$

Option $B$ is correct.