Electro magnetic induction practice · Medium

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.

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

The unit of magnetic flux density is

Identify the incorrect statement. Induced electric field

If $\mathrm{10}\,\,\mathrm{A}$ deposits $\mathrm{10}\mathrm{.8 \,\,g}$ of silver in $\mathrm{25}\,\,\mathrm{min}$, how much copper would deposit when $\mathrm{9}\,\,\mathrm{A}$ current flows for $\mathrm{20}\,\,\mathrm{min}$.?

Magnetic energy density in an inductor is given by

Lenz's law gives

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

The particle accelerator that uses the phenomenon of electromagnetic induction is the

If the magnetic flux is expressed in $weber$, then magnetic induction can be expressed in

A square conducting loop of side $L$ is situated in gravity-free space. A small conducting circular loop of radius $r(r \ll L)$ is placed at the center of the square loop, with its plane perpendicular to the plane of the square loop. The mutual inductance of the two coils is

Statement (A): The alternating current lags behind the e.m.f. by a phase angle of $\frac{\pi }{2},$ when ac flows through an inductor.
Statement (B): A bulb connected in series with a solenoid is connected to ac source. If a soft iron core is introduced in the solenoid, the bulb will glow brighter.
Statement (C): The dc and ac both can be measured by a hot wire instrument.

A diamagnetic rod is placed vertically between the poles of an electromagnet when the current in the
electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field, Hence the
rod gains gravitational potential energy. The work required to do this comes from.

A flat rectangular coil is placed in a uniform magnetic field and rotated about an axis passing through its centre, parallel to its shorter edges and perpendicular to the field. The maximum flux linked and maximum induced emf are $\phi$ and $\mathrm{E}$ respectively. If the axis is shifted to coincide with one of the shorter edges, then

A circular coil of area $300 \mathrm{~cm}^2$ and 25 turns rotates about its vertical diameter with an angular speed of $40 \mathrm{~s}^{-1}$ in a uniform horizontal magnetic field of magnitude $0.05 \mathrm{~T}$. Obtain the maximum voltage induced in the coil.

If a coil of $\mathrm{40}$ turns and area $\mathrm{4}\mathrm{.0}\,\,\mathrm{c}{\mathrm{m}^\mathrm{2}}$ is suddenly removed from a magnetic field, it is observed that a charge of $2.0\,\, \times {10^{ - 4}}\,\,\mathrm{C}$ flows into the coil. If the resistance of the coil is $\mathrm{80}\,\,\mathrm{\Omega }$, the magnetic flux density in $\mathrm{Wb}{\mathrm{m}^{ - 2}}$ is

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

The pointer of a dead-beat galvanometer gives a steady deflection because

Van De graff generator is used to

A magnetic field is directed into the page and changes with time according to the expression $B=\left(0.03 t^2+1.4\right) T$, where $t$ is in seconds. The field has a circular cross section of radius $R$ when $\mathrm{t}=3.0 \mathrm{~s}$ and $\mathrm{r}=0.02 \mathrm{~m}$.