Electro magnetic induction practice · Mixed difficulty

The back e.m.f. induced in a coil, when current changes from $1 \mathrm{~A}$ to $0 \mathrm{~A}$ in 1 milli-second is $4 \mathrm{~V}$. The self-inductance of the coil is ____

Assertion: A metallic surface is moved in and out in magnetic field then emf is induced in it.
Reason: Eddy current will be produced in a metallic surface moving in and out of magnetic field.

A metallic metre stick moves with a velocity of $2 \mathrm{~m} \mathrm{~s}^{-1}$ in a direction perpendicular to its length and perpendicular to a uniform magnetic field of magnitude $0.2 \mathrm{~T}$. Find the emf induced between the ends of the stick.

When the number of turns in the two circular coils closely wound are doubled (in both), their mutual inductance becomes

Magnetic flux linked with a coil is $\phi = 5\,{t^2} + 2\,t + 3$, where $t$ is second and $\phi$ is in weber. At time $t = 1\mathrm{ }s$, the value of induced emf in volt

Changing magnetic fields can set up current loops
in nearby metal bodies and the currents are called
as

If $\mathrm{N}$ is the number of turns in a coil, the value of self inductance varies as

Magnetic flux linked with a coil is $\phi = 5\,{t^2} + 2\,t + 3$, where $t$ is second and $\phi$ is in weber. At time $t = 1\mathrm{ }s$, the value of induced emf in volt

Mutual inductance of two coils can be increased by

A $12 \, \mathrm{V}$ battery connected to a coil of resistance $6 \, \Omega$ through a switch, drives a constant current in the circuit. The switch is opened in $1 \, \mathrm{ms}$. The emf induced across the coil is $20 \, \mathrm{V}$. The inductance of the coil is :

Two inductances each of inductance ‘L’ are joined in parallel their equivalent inductance is

A train is running at a speed of $72 \mathrm{~km} \mathrm{~hr}^{-1}$ on the rails separated by a distance of $150 \mathrm{~cm}$. If the vertical component of earth's magnetic field at the place is $4.0 \times 10^{-5} \mathrm{~T}$. The induced emf on the rails is

The magnitude of induced emf is directly proportional to the rate of change of magnetic flux linked with the coil. This statement is known as

The momentum in mechanics is expressed as $m\,\, \times \,\,V$. The analogous expression in electricity is

A 10-meter wire is kept in east-west direction. It is falling down with a speed of $5.0 \mathrm{~meter} / \mathrm{second}$, perpendicular to the horizontal component of earth's magnetic field of $0.30 \times 10^{-4}$ weber $/$ meter $^2$. The momentary potential difference induced between the ends of the wire will be

An inductor coil stores $32 \mathrm{~J}$ of magnetic field energy and dissipates energy as heat at the rate $320 \mathrm{~W}$ when a current of $4 \mathrm{~A}$ is passed through it. The time constant of the circuit when this coil is joined across an ideal battery will be

Faraday's law among the following is ____

The energy stored in an inductor of self inductance $L$ henry carrying a current of $\mathrm{1 }\,\mathrm{A}$ is

The mutual inductance between two coils is $0.09$ Henry. If the current in the primary coil changes from 0 to $20 \mathrm{~A}$ in $0.006 \mathrm{~s}$, the e.m.f. induced in the secondary coil at that instant is

Two identical circular coils A and B are kept on a horizontal tube side by side without touching each other. If the current in the coil A increases with time, in response, the coil B :

The currents in two coils of self- inductance $5 \mathrm{~mH}$ and $1 \mathrm{~mH}$ are increasing at the same rate at a certain instant. The power supplied to the coils is also same. Then identify the false statement among the following

A solenoidal coil has 50 turns per $\mathrm{cm}$ along its length and a cross-sectional area of $4 \times 10^{-4} \mathrm{~m}^2 .200$ turns of another wire is wound round the first solenoid co-axially. Both the two coils are electrically insulated from each other. Calculate the mutual inductance between the two coils.

Coefficient of coupling between two coils of self-inductances ${L_1}\,\,\mathrm{and}\,\,{L_2}$ is unity. It means

Assertion : A small magnet takes longer time in falling in a hollow metallic tube without touching the wall.

Reason : There is opposition of motion due to production of eddy currents in metallic tube.

Lenz's law provides a relation between

A short solenoid of radius $a$, number of turns per Unit length $n_1$ and length $L$ is kept coaxially inside a very long solenoid of radius $b$, the number of turns per Unit length $n_2$. What is the mutual inductance of the system?

In $\mathrm{0}\mathrm{.1 s}$, the current in a coil increases from $\mathrm{1}\,\mathrm{A}$ to $\mathrm{1.5}\,\mathrm{A}$. If inductance of coil is $\mathrm{60}\,\,\mathrm{mH}$, then induced current in external resistance of $3\,\mathrm{\Omega }$ will be

Two inductors $\mathrm{A}$ and $\mathrm{B}$ when connected in parallel are equivalent to a single inductor of inductance $1.5 \mathrm{~H}$, and when connected in series are equivalent to a single inductor of inductance $8 \mathrm{~H}$. Find the difference in the inductances of $\mathrm{A}$ and $\mathrm{B}$.

Self induction of a solenoid is

If a bar magnet is dropping through the copper ring, then its velocity