JEE PHYSICS MCQ: ELECTRO MAGNETIC INDUCTION

1 Medium

1 of 1

Application +4 | -1

A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The number of turns is n and the cross sectional area of the coil is

A

. When the coil turns through

{180^0}

about its diameter, the charge flowing through the coil is

Q

. The total resistance of the circuit is

R

. What is the magnitude of the magnetic induction

View answer and explanation

Correct option: D

\frac{{QR}}{{2nA}}

Option A (

\frac{{QR}}{{nA}}

) is incorrect. Option B (

\frac{{2QR}}{{nA}}

) is the correct answer because the magnetic induction is derived from Faraday's law of induction and the charge flowing through the coil.

More Questions from ELECTRO MAGNETIC INDUCTION

Practice All Chapter MCQs →

The current in a long solenoid of radius

R

and having

n

turns per unit length is given by

i=i_0 \sin \omega t

. A coil having

N

turns is wound around it near the centre. Find the induced emf in the coil. The induced emf can be produced in a coil by

A. moving the coil with uniform speed inside
uniform magnetic field

B. moving the coil with non uniform speed inside
uniform magnetic field

C. rotating the coil inside the uniform magnetic
field

D. changing the area of the coil inside the uniform
magnetic field

Choose the correct answer from the options given
below: An inductance coil have the time constant

4 \mathrm{sec}

, if it is cut into two equal parts and connected parallel then new time constant of the circuit- If the coils of a transformer are made up of thick wire, then A loop of area

0.1\,\,{m^2}

rotates with a speed of

\mathrm{60}

rps perpendicular to a magnetic field of

\mathrm{0}\mathrm{.4}\,\,\mathrm{T}

. If there are

\mathrm{100}

turns in the loop, maximum voltage induced in the loop is A

\mathrm{50}\,\,\mathrm{mH}

coil carries a current of

\mathrm{2 A}

, the energy stored in joule is