An air core solenoid has $1000$ turns and is one metre long. Its cross-sectional area is $10 \, cm^2$. Its self-inductance is: (in $, mH$)

An air-cored solenoid with length $20 \, cm$,area of cross-section $20 \, cm^2$,and number of turns $400$ carries a current of $2 \, A$. The current is suddenly switched off within $10^{-3} \, s$. The average back $emf$ induced across the ends of the open switch in the circuit is (ignore the variation in magnetic field near the ends of the solenoid) ........ $V$.

An air-cored solenoid with $30 \ cm$ length,area of cross-section $25 \ cm^2$,and $500$ turns carries a current of $2.5 \ A$. The current is suddenly switched off in a brief time of $10^{-3} \ s$. How much is the average back emf induced across the ends of the open switch in the circuit (in $V$)? (Ignore the variation in magnetic field near the ends of the solenoid.)

In an induction coil with resistance,the induced emf will be maximum when

In a circuit,the current falls from $14 \ A$ to $4 \ A$ in a time $0.2 \ ms$. If the induced emf is $150 \ V$,then the self-inductance of the circuit is:

What will be the self-inductance of a coil of $100$ turns if a current of $5 \ A$ produces a magnetic flux of $5 \times 10^{-5} \ Wb$?