Electro magnetic induction practice · Mixed difficulty

If coil is open then $L$ and $R$ become

When the number of turns and the length of the solenoid are doubled keeping the area of cross-section same, the inductance

Whenever a magnet is moved either towards or away from a conducting coil, an emf is induced, the magnitude of which is independent of

When a wire loop is rotated in a magnetic field, the direction of induced e.m.f. changes one in each

Induction furnace uses ……… to produce heat.

The electromagnetic force induced in coil is given by

The direction of induced current in a conductor when moved in a magnetic field can be determined by

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

Self-inductance of two coils is $2 \mathrm{H} \& 8 \mathrm{H}$. If $50 \%$ flux of primary coil is linked with secondary coil, then find coefficient of mutual inductance.

If the current $3.0 \mathrm{~A}$ flowing in the primary coil is made zero in $0.1 \mathrm{~sec}$, the emf induced in the secondary coil is $1.5$ volt. The mutual inductance between the coils is

The magnetic flux $\phi$ (in weber) linked with a coil of resistance $10 \Omega$ varies with time $t$ (in second) as $\phi=8 {t}^2-4 t+1$. The current induced in the coil at $t=0.1 \mathrm{~sec}$ is

In a region at a distance $r$ from $z$-axis, magnetic field $\vec{B}=B_0 r t \hat{k}$ is present where $B_0$ is constant and $t$ is time. Then the magnitude of induced electric field at a distance $r$ from $z$-axis is given by

The magnetic flux linked with a coil of resistance $2\,\,\,\Omega$ at any instant is given by $\phi = 5{t^2} - 10t + 50\,\,\,{\text{weber}}.$ The emf in the coil at $t = 2\,\,\,{\text{seconds}}$ is

A square loop of wire, side length $\mathrm{10}\,\,\mathrm{cm}$ is placed at angle of $\mathrm{45}^\circ$ with a magnetic field that changes uniformly from $\mathrm{0}\mathrm{.1 T}$ to zero in $\mathrm{0}\mathrm{.7 s}$. The induced current in the loop (its resistance is $\mathrm{1}\,\,\mathrm{\Omega })$ is

For a current carrying inductor, emf associated is $20 \mathrm{~m} \mathrm{V}$. Now, current through it changes from $6 \mathrm{~A}$ to $2 \mathrm{~A}$ in $2 \mathrm{~s}$. The coefficient of mutual inductance is

Assertion: Eddy currents are produced in any metallic conductor when magnetic flux is changed around it.

Reason: Electric potential determines the flow of charge.

If magnetic monopoles exists then Gauss's law in magnetism can be written as

Mutual inductance of a pair of coils, depend
on

Two cells of emf 1.25 V, 0.75 V and each of internal resistance $1\,\Omega$ are connected in parallel. The effective emf will be

Assertion : The mutual inductance of two coils is doubled if the self inductance of the primary
or secondary coil is doubled.

Reason : Mutual inductance is proportional to the self inductance of primary and secondary
coils.

Statement I: No current is induced in a metal loop if it is rotated in an electric field.

Statement II: The electric flux through the loop does not change with time.

An emf is 15 V is applied in a circuit coil containing 5 H inductance and 10 Ω resistance. The ratio of currents at time $t = \infty$ and t=1 s is

An infinitely cylinder is kept parallel to an uniform magnetic field $B$ directed along positive $z$ axis. This direction of induced current as seen from the $z$ axis will be

The induction coil works on the principle of

Consider the following statements.

(a) Eddy current loss is minimized by using laminated cores.

(b) Self-inductance is called inertia of electricity.

Choose the correct statements:

Fleming’s left and right hand rule are used in

Assertion: When a conducting rod moves in uniform transverse magnetic field with uniform speed which is perpendicular to its length, then potential difference may develop across its ends.

Reason: In any conductor, free electrons and free positive ions are available.

A particle mass m, charge Q and kinetic
energy T enters a transverse uniform
magnetic field of induction B after 3s the
kinetic energy of the particle will be

In a magnetic field of $0.05\,\,T$, area of a coil changes from $101\,\,c{m^2}$ to $100\,\,c{m^2}$ without changing the resistance which is $2\,\,\mathrm{\Omega }$. The amount of charge that flow during this period is

Current in a circuit falls from 5.0 A to 0 A in 0.1 s. If an average emf of 200 V is induced, estimate the self-inductance of the circuit