Electro magnetic induction practice · Mixed difficulty

The unit of magnetic flux density is

A circular coil of area $0.01 \mathrm{~m}^2$ and 40 turns is rotated about its vertical diameter with an angular speed of $50 \mathrm{~rad~s}^{-1}$ in a uniform horizontal magnetic field $0.05 \mathrm{~T}$. If the average power loss due to joule heating is $25 \mathrm{~m W}$. Then, the closed loop resistance of the coil 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 $\mathrm{r}=0.02 \mathrm{~m}$.

The working of a dynamo is based on the principle of

A uniform magnetic field $B$ exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field changes with time at a steady rate $\mathrm{d}B/dt = \mathrm{0}\mathrm{.032 \,\,T}{\mathrm{s}^{ - 1}}\mathrm{.}$ The induced current in the loop is close to (Take, resistivity of the metal wire $= 1.\mathrm{23} \times \mathrm{1}{\mathrm{0}^{ - 8}}\Omega \mathrm{m)}$

Two parallel rails of a railway track insulated from each other and with the ground are connected to a millivoltmeter. The distance between the rails is one metre. A train is travelling with a velocity of $72\,\,km{\mathrm{h}^{ - 1}}$ along the track. The reading of the millivotmeter (in $\mathrm{mV}$) is : (Vertical component of the earth’s magnetic induction is $2\,\, \times {10^{ - 5}}\,\mathrm{T})$

If a coil of metal wire is kept stationary in a non-uniform magnetic field, then

A conductor of length $l$ is kept in a magnetic field of strength $\mathrm{B}$. A current $\mathrm{I}$ passes through the conductor. The force experienced by the conductor is proportional to

Assertion: Faraday's copper disc generator is based on dynamic electromagnetic induction.

Reason: Alternating current generator is based on periodic electromagnetic induction.

A horizontal straight conductor when placed along south-north direction falls under gravity; there is

Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon

Assertion (A) : If some ferromagnetic substance is filled inside a solenoid, its coefficient of self induction $L$ will increase.

Reason (R) : By increasing the current in a coil, its coefficient of self induction $L$ can be increased.

Assertion : An emf is induced in long solenoid by a small bar magnet that moves while totally inside it along the solenoid axis.

Reason : As the magnet moves inside the solenoid, the flux through individual turns of the solenoid does not change.

Magnetic flux is