Electromagnetic Induction

If 0.1 J of energy is stored for the flow of current of 0.2 A in an inductor, then its inductance value is

• 5 H

• 0.5 H

• 5 mH

• 50 H

The self-inductance of a long solenoid carrying current is independent of

• its length

• the current

• its cross-sectional area

• magnetic permeability of the core

The polarity of induced emf is given by

• Ampere's circuital law

• Biot-Savart's law

• Lenz's law

• Fleming's right hand rule

A conducting ring of radius 1 m kept in a uniform magnetic field B of 0.01 T, rotates uniformly with an angular velocity 100 rads^-1 with its axis of rotation perpendicular to B. The maximum induced emf in it is

• $1.5 \mathrm{\pi } \mathrm{V}$

• $\mathrm{\pi } \mathrm{V}$

• $2\mathrm{\pi } \mathrm{V}$

• $0.5 \mathrm{\pi } \mathrm{V}$

The self-inductance of an air core solenoid of 100 turns is 1 mH. The self-inductance of another solenoid of 50 turns (with the same length and cross-sectional area) with a core having relative permeability 500 is

• 125 mH

• 24 mH

• 60 mH

• 30 mH

The magnetic flux linked with a coil of N turns of area of cross-section A held with its plane parallel to the field B is

• $\frac{\mathrm{NAB}}{2}$

• NAB

• $\frac{\mathrm{NAB}}{4}$

• 0

Two identical coaxial coils P and Q carrying equal amount of current in the same direction are brought nearer. The current in

• P increases while in Q decreases

• Q increases while in P decreases

• both P and Q increases

• both P and Q decreases

The self inductance of a long solenoid cannot be increased by

• increases its area of cross section

• increasing its length

• increasing the current through it

• increasing the number of turns in it

A 5O Hz AC current of peak value 2 A flows through one of the pair of coils. If the mutual inductance between the pair of coils is 150 mH, then the peak value of voltage induced in the second coil is

• $30 \mathrm{\pi V}$

• $60 \mathrm{\pi V}$

• $15 \mathrm{\pi V}$

• $300 \mathrm{\pi V}$

In the total electromagnetic energy falling on a surface is U, then the total momentum delivered (for complete absorption) is

• $\frac{\mathrm{U}}{\mathrm{c}}$

• cU

• $\frac{\mathrm{U}}{{\mathrm{c}}^2}$

• c²U