An $e.m.f.$ of $12 \, V$ is produced in a coil when the current in it changes at the rate of $45 \, A/min$. The inductance of the coil is ....... $H$.

In the given circuit, if $\frac{dI}{dt} = -1 \, A/s$, then the value of $(V_A - V_B)$ at this instance will be (in $\, V$)

$A$ coil of $Cu$ wire (radius $r$,self-inductance $L$) is bent into two concentric turns,each having a radius of $r/2$. What is the new self-inductance?

The ratio of the number of turns per unit length of two solenoids $A$ and $B$ is $1: 3$ and the lengths of $A$ and $B$ are in the ratio $1: 2$. If the two solenoids have the same cross-sectional area,the ratio of the self-inductances of the solenoids $A$ and $B$ is

Current in a circuit falls from $5.0 \, A$ to $0.0 \, A$ in $0.1 \, s$. If an average $emf$ of $200 \, V$ is induced,give an estimate of the self-inductance of the circuit in $Henry$.

$A$ coil of self-inductance $L$ is connected in series with a bulb and an a.c. source. Brightness of the bulb decreases when