Self Inductance and Mutual Inductance

Three inductances $L_1=0.75 \mathrm{H}$, $L_2=L_3=0.5 \mathrm{H}$ are connected as shown below. Assuming no coupling, the resultant inductance will be

Two induction coils of inductance $L_1$ and $L_2$ are separated by a considerable distance. On connecting them in series, the equivalent inductance will be

The mutual inductance of a pair of coils is $0.75 \mathrm{H}$. If the current in the primary coil changes from $0.5 \mathrm{A}$ to $0$ in $0.01 \mathrm{s}$, then the average induced e.m.f. in the secondary coil is

Choke coil works on the principle of

A small square loop of wire of side is placed inside a large square loop of wire of side $L\left(L>>l\right)$. The loops are co-planar and their centres coincide. The mutual inductance of the system is proportional to

A solenoid has $2000$ $\mathrm{turns}$ wound over a length of $0.30 \mathrm{m}$. The area of its cross-section is $1.2\times {10}^{-3} {\mathrm{m}}^2$. Around its central section, a coil of $300$ $\mathrm{turn}$ is wound. If an initial current of $2 \mathrm{A}$ in the solenoid is reversed in $0.25 \mathrm{s},$ then the emf induced in the coil is

A superconducting loop of radius $R$ has self inductance $L$. A uniform and constant magnetic field $B$ is applied perpendicular to the plane of the loop. Initially current in this loop is zero. The loop is rotated by $180°.$ The current in the loop after rotation is equal to-

When the current $i$ in a certain inductor coil is $5.0 \mathrm{A}$ and is increasing at the rate of $10.0 \mathrm{A} {\mathrm{s}}^{-1}$, the potential difference across the coil is $140 \mathrm{V}$. When the current is $5.0 \mathrm{A}$ and decreasing at the rate of $10.0 \mathrm{A} {\mathrm{s}}^{-1}$, the potential difference is $60 \mathrm{V}$. The self inductance of the coil is -

A coil of radius $1 \mathrm{cm}$ and number of turns $100$ is placed in the middle of a long solenoid of radius $5 \mathrm{cm}$ and having $5 \mathrm{turns} {\mathrm{cm}}^{-1}$. The mutual induction in millihenry will be

The energy stored in an electromagnet is $400 \mathrm{mJ}$ when a current $2 \mathrm{A}$ flows in the coils. The self-inductance of the coil is 

A circular current carrying coil has a radius $R$. The distance from the centre of the coil on the axis, where the magnetic induction will be ${\frac{1}{8}}^{\mathrm{th}}$ to its value at the centre of the coil is

A circular coil of radius $5 \mathrm{cm}$ has $500$ turns of a wire. The approximate value of the coefficient of self-induction of the coil will be

The inductance of a closed-packed coil of $400$ turns is $8 \mathrm{mH}$. A current of $5 \mathrm{mA}$ is passed through it. The magnetic flux through each turn of the coil is

A wire of fixed length is wound on a solenoid of length $l$ and radius $r$. Its self-inductance is found to be $L$. Now if the same wire is wound on a solenoid of length $\frac{l}{2}$ and radius $\frac{r}{2}$, then the self inductance will be

Average energy stored in a pure inductance $L$ when a current $i$ flows through it, is

The mutual inductance of a pair of coils is $0.75 \mathrm{H}$. If current in the primary coil changes from $0.5 \mathrm{A}$ to zero in $0.01 \mathrm{s}$, find average induced emf in secondary coil.

The back emf induced in a coil, when current changes from $1 \mathrm{A}$ to zero in $1 \mathrm{ms}$, is $4 \mathrm{V}$, the self-inductance of the coil is

A coil having $50$ turns has self-inductance of $10 \mathrm{mH}$. On increasing the number of turns to $150$, the self-inductance is 

An electric motor has a back emf of $110 \mathrm{V}$ and armature current of $90 \mathrm{A}$. The armature is making $24.5 \mathrm{rps}$. Then the power developed is 

The mutual inductance of a pair of coils is $2 \mathrm{H}$. If the current in the coils changes from $10 \mathrm{A}$ to zero in $0.1 \mathrm{s}$, the emf induced in the other coil is