If $R$ and $L$ represent respectively resistance and self-inductance,which of the following combinations has the dimensions of frequency?

The current in a coil changes from $2 \,A$ to $5 \,A$ in $0.3 \,s$. The magnitude of emf induced in the coil is $1.0 \,V$. The value of self-inductance of the coil is (in $\,mH$)

For a toroid,$N = 500$,radius $R = 40 \text{ cm}$,and area of cross-section $A = 10 \text{ cm}^2$. Find the inductance in $\mu\text{H}$.

The self-inductance $L$ of a solenoid of length $l$ and area of cross-section $A$,with a fixed number of turns $N$,increases as:

Two identical inductors carry currents that vary with time according to linear laws (as shown in the figure). In which of the two inductors is the self-induced $emf$ greater?

$A$ long solenoid has $500$ turns. When a current of $2 \, A$ is passed through it,the resulting magnetic flux linked with each turn of the solenoid is $4 \times 10^{-3} \, Wb$. The self-inductance of the solenoid is ....... $H$.