In a certain region static electric and magnetic fields exist. The magnetic field is given by B → = B 0 i ^ + 2 j ^ - 4 k ^ . If a test charge moving with a velocity v → = v 0 3 i ^ - j ^ + 2 k ^ experiences no force in that region, then the electric field in the region, in SI units, is:

E → = - v 0 B 0 14 j ^ + 7 k ^

E → = - v 0 B 0 i ^ + j ^ + 7 k ^

E → = - υ 0 B 0 3 i ^ - 2 j ^ - 4 k ^

The electric fields of two plane electromagnetic plane waves in vacuum are given by E 1 → = E 0 cos ω t - k x j ^ and E 2 → = E 0 cos ω t - k y k ^ , at t = 0 , a particle of charge q is at origin with a velocity v → = 08 c j ^ ( c is the speed of light in vaccum). The instantaneous force experienced by the particle is:

E 0 q 0 .8 i ^ + j ^ + 0 .2 k ^

E 0 q 0 .8 i ^ - j ^ + 0 .4 k ^

E 0 q 0 .4 i ^ - 3 j ^ + 0 .8 k ^

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An iron rod is placed parallel to magnetic field of intensity $2000 A m$ . The magnetic flux through the rod is $6 \times 10^{- 4} Wb$ and its cross-sectional area is $3 c m^{2}$ . The magnetic permeability of the rod in $W b A^{- 1} m^{- 1}$ is

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Important Questions on Physics

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An ideal transformer converts

220 V

AC to

3.3 kV

AC. It transmits the power of

4.4 kW

. If the primary coil has

600

turns, then alternating current in the secondary coil is

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General Knowledge>General Science>Physics>Magnetism

In a certain region static electric and magnetic fields exist. The magnetic field is given by

\vec{B} = B_{0} (\hat{i} + 2 \hat{j} - 4 \hat{k})

. If a test charge moving with a velocity

\vec{v} = v_{0} (3 \hat{i} - \hat{j} + 2 \hat{k})

experiences no force in that region, then the electric field in the region, in SI units, is:

MEDIUM

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Consider the regular array of vertical identical current-carrying wires (with the direction of current flow as indicated in the figure below) protruding through a horizontal table. If we scatter some diamagnetic particles on the table, they are likely to accumulate-

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The shape of the path of free electron in a metal is _____:

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When the current in a coil changes from

5 A

2 A

0 .1 s

, an average voltage of

50 V

is produced. The self-inductance of the coil is

HARD

General Knowledge>General Science>Physics>Magnetism

Nickel

(Z = 28)

combines with a uninegative monodentate ligand to form a diamagnetic complex

{[{NiL}_{4}]}^{2 -} .

The hybridisation involved and the number of unpaired electrons present in the complex are respectively:

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General Knowledge>General Science>Physics>Magnetism

An electron enters a chamber in which a uniform magnetic field is present as shown. Ignore gravity
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During its motion inside the chamber

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Consider a circular coil of wire carrying constant current

I,

forming a magnetic dipole. The magnetic flux through an infinite plane that contains the circular coil and excluding the circular coil area is given by

ϕ_{i}

The magnetic flux through the area of the circular coil area is given by

ϕ_{0}

. Which of the following option is correct?

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General Knowledge>General Science>Physics>Magnetism

If one were to apply the Bohr model to a particle of mass

' m'

and charge

' q'

moving in a plane under the influence of a magnetic field 'B', the energy of the charged particle in the

n^{t h}

level will be:

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A transformer of efficiency

90 %

has turns ratio

10 : 1 .

If the voltage across the primary is

220 V

and current in the primary is

0.5 A,

then the current in secondary is

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A transformer consisting of

300

turns in the primary and

150

turns in the secondary gives output power of

2.2 k W

. If the current in the secondary coil is

10 A

, then the input voltage and current in the primary coil are:

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A power transmission line feeds input power at

2300 V

to a step down transformer with its primary windings having

4000

turns. The output power is delivered at

230 V

by the transformer. If the current in the primary of the transformer is

5 A

and its efficiency is

90 %

, the output current would be:

MEDIUM

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Two magnetic dipoles $X$ and $Y$ are placed at a separation $d$ , with their axes perpendicular to each other. The dipole moment of $Y$ is twice that of $X$ . A particle of charge $q$ is passing through their mid-point $P$ , at angle $θ = 45^{o}$ with the horizontal line, as shown in figure. What would be the magnitude of force on the particle at that instant? ( $d$ is much larger than the dimension of the dipole)
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An example of a perfect diamagnet is a superconductor. This implies that when a superconductor is put in a magnetic field of intensity

B

, the magnetic field

B_{s}

inside the superconductor will be such that

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A transformer having efficiency of

90 %

is working on

200 V

and

3 k W

power supply. If the current in the secondary coil is

6 A

the voltage across the secondary coil and the current in the primary coil respectively are:

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Earth Attracts particles because of _____:

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The electric fields of two plane electromagnetic plane waves in vacuum are given by

\vec{E_{1}} = E_{0} \cos (ω t - k x) \hat{j}

and

\vec{E_{2}} = E_{0} \cos (ω t - k y) \hat{k}

, at

t = 0,

a particle of charge

q

is at origin with a velocity

\vec{v} = 08 c \hat{j}

(

c

is the speed of light in vaccum). The instantaneous force experienced by the particle is:

MEDIUM

General Knowledge>General Science>Physics>Magnetism

An electron enters a chamber in which a uniform magnetic field is present as shown.
Question Image

An electric field of appropriate magnitude is also applied so that the electron travels un-deviated without any change in its speed through the chamber. We are ignoring gravity. Then, the direction of the electric field is,

HARD

General Knowledge>General Science>Physics>Magnetism

A circular loop of radius

0.3 cm

lies parallel to a much bigger circular loop of radius

20 cm

. The centre of the small loop is on the axis of the bigger loop. The distance between their centres is

15 cm

. If a current of

2.0 A

flows through the smaller loop, then the flux linked with a bigger loop is:

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The magnetic susceptibility is negative for:

An iron rod is placed parallel to magnetic field of intensity 2000 A m. The magnetic flux through the rod is 6×10-4 Wb and its cross-sectional area is 3 cm2. The magnetic permeability of the rod in Wb A-1m-1 is

Important Questions on Physics

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An iron rod is placed parallel to magnetic field of intensity $2000 A m$ . The magnetic flux through the rod is $6 \times 10^{- 4} Wb$ and its cross-sectional area is $3 c m^{2}$ . The magnetic permeability of the rod in $W b A^{- 1} m^{- 1}$ is