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The current through a coil of self-inductance L=2mH is given by $i = t^{2} e^{- t}$ at time t. How long it will take to make the emf zero?

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Important Questions on Electromagnetic Induction

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

Consider two coils of radii $r_{1}$ and $r_{2}$ , placed at a distance $d$ away as shown in the figure. Assuming the length of the coils $l_{1}, l_{2} ≫ d$ with $n_{1}, n_{2}$ the number of turns per unit length of the two coils respectively, the mutual inductance of the two coils is

Question Image

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

Two inductors $L_{1}$ and $L_{2}$ are connected in parallel and a time varying current flows as shown in figure. The ratio ot current $\frac{i_{1}}{i_{2}}$ at any ime $t$ Is Question Image

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The average emf induced in a coil, when the current in it changes from

2 A

4 A

0.05 s

, is

8 V

. Find the self-inductance of this coil.

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The self induced emf of a coil is

25

volts. When the current in it is changed at uniform rate from

10 A

25 A

1 s

, the change in the energy of the inductance is:

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

A long solenoid has

500

turns. When a current of

2 A

is passed through it, the resulting magnetic flux linked with each turn of the solenoid is

4 \times 10^{- 3} Wb

, then self-inductance of the solenoid is

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

Consider a conducting wire of length

L

bent in the form of a circle of radius

R

and another conductor of length

a (a < < R)

is bent in the form of a square. The two loops are then placed in same plane such that the square loop is exactly at the centre of the circular loop. What will be the mutual inductance between the two loops?

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

In an inductor of self-inductance

L = 2 mH

, current changes with time according to relation

i = t^{2} e^{- 1}

. At what time

e m f

is zero?

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

If a change in current of

0.01 A

in one coil produces a change in magnetic flux

2 \times 10^{- 2}

weber in another coil, then the mutual inductance between coils is

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The total number of turns and cross-section area in a solenoid is fixed. However, its length

L

is varied by adjusting the separation between windings. The inductance of solenoid will be proportional to:

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

Two coils

' P'

and

' Q'

are separated by some distance. When a current of

3 A

flows through coil

' P^{'},

a magnetic flux of

10^{- 3} W b

passes through

' Q^{'} .

No current is passed through

' Q^{'} .

When no current passes through

' P'

and a current of

2 A

passes through

' Q^{'},

the flux through

' P'

is:

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The self inductance

L

of a solenoid of length

l

and area of cross-section

A

, with a fixed number of turns

N

increases as

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The primary and the secondary coils of a transformer contains

10

and

100

turns

respectively. The primary coil is connected to a battery that supplies a constant voltage of

1.5 V

. The voltage across the secondary coil is

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

If the inductance of a coil is

1 H

, its effective resistance in a

DC

circuit will be

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

Two coaxial coils

A

and

B

of radii

R_{1}

and

R_{2}

are placed in the same plane.

(R_{2} > R_{1})

. If a current is passed through coil

B

, the coefficient of mutual inductance between the coils is proportional to

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The mutual inductance between two coils depends upon

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

A coil of wire of

1000

turns has self inductance

120

millihenry. The self inductance of a coil

250

turn is

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

The inductance in a coil plays the same role as

MEDIUM

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

A series

L - R

circuit is connected to a battery of emf

V

. If the circuit is switched on at

t = 0

, then the time at which the energy stored in the inductor reaches

(\frac{1}{n})

times of its maximum value, is :

HARD

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

A small circular loop of wire of radius

a

is located at the centre of a much larger circular wire loop of radius

b

. The two loops are in the same plane. The outer loop of radius

b

carries an alternating current

I = I_{0} \cos (ω t) .

The emf induced in the smaller inner loop is nearly:

EASY

Physics>Electricity and Magnetism>Electromagnetic Induction>LC Oscillations

A long solenoid has

1000

turns. When a current of

4 A

flows through it the magnetic flux linked with each turn of the solenoid is

4 \times 10^{- 3} Wb.

The self-inductance of the solenoid is:

The current through a coil of self-inductance L=2mH is given by i=t2e-t at time t. How long it will take to make the emf zero?

Important Questions on Electromagnetic Induction

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The current through a coil of self-inductance L=2mH is given by $i = t^{2} e^{- t}$ at time t. How long it will take to make the emf zero?