Question

Self inductance of a long solenoid depends upon following(s)-

• A. number of turns
• B. radius of solenoid
• C. length of solenoid
• D. none of these

Answer 1

Answer: (A), (B), (C)

The correct options are
A radius of solenoid
B number of turns
C length of solenoid

$N$=total number of turns in solenoid

$l$=length of solenoid

$R$=radius of cross section of solenoid

Magnetic field inside solenoid =$B={\mu }_o\frac{N}{l}i$ where, $\frac{N}{l}$=number of turns per unit length

Now, emf induced= $E=NBA$

$⟹E=N\times {\mu }_o\frac{N}{l}i\times \pi R^2$

$⟹E=\frac{{\mu }_o{N}^2\pi R^2}{l}i=Li$

where $L$=self inductance

Thus, $L=\frac{{\mu }_o{N}^2\pi R^2}{l}$

Hence, $L$ depends on $N$, $R$ and $l$.

Answer-(A),(B),(C)