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A circular loop and a square loop are formed from two wires of same length and cross section. Same current is passed through them. Then the ratio of their dipole moments is

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Important Questions on Magnetic Effect of Electric Current

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

A wire of length

L

metre carrying a current of

I

ampere is bent in the form of a circle. Its magnetic moment is,

HARD

Science>Physics>Magnetic Effect of Electric Current>Magnet

A rectangular loop of sides $10 cm$ and $5 cm$ , carrying a current $I$ of $12 A$ , is placed in different orientations as shown in the figure below.
(a) Question Image (b)

(c) (d)

If there is a uniform magnetic field of $0.3 T$ in the positive $z$ direction, in which orientations the loop would be in $(i)$ stable equilibrium and $(ii)$ unstable equilibrium?

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

An iron rod of volume

10^{- 3} m^{3}

and relative permeability

1000

is placed as core in a solenoid with

10 turns {cm}^{- 1}

. If a current of

0.5 A

is passed through the solenoid, then the magnetic moment of the rod will be :

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

A proton is revolving on a circular path of radius

2 mm

with frequency

10 Hz

. Magnetic dipole moment associated with proton is

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

A rectangular coil of length

0.12 m

and width

0.1 m

having

50

turns of wire is suspended vertically in a uniform magnetic field of strength

0.2

W e b e r / m^{2}

. The coil carries a current of

2 A

. If the plane of the coil is inclined at an angle of

30^{o}

with the direction of the field, the torque required to keep coil in stable equilibrium will be:

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

The ratio of angular momentum

L

to the atomic dipole moment

μ_{i}

for hydrogen like atoms and ions is

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

A coil of $50$ turns carrying a current of $2 A$ in a magnetic field of $0.5 T$ . The torque acting on the coil is

Question Image

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

A bar magnet is held perpendicular to uniform magnetic field. The torque acting on the magnet is to be made half by rotating it. It should be rotated through an angle

(\sin 30 ° = 0.5, \sin 90 ° = 1)

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

A square loop is carrying a steady current

I

and the magnitude of its magnetic dipole moment is

m

. If this square loop is changed to a circular loop and it carries the same current, the magnitude of the magnetic dipole moment of circular loop will be:

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

Following figures show the arrangement of bar magnets in different configurations. Each magnet has magnetic dipole

\vec{m} .

Which configuration has highest net magnetic dipole moment?

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

In a permanent magnet at room temperature

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

The dipole moment of a circular loop carrying a current I, is m and the magnetic field at the centre of the loop is

B_{1}

. When the dipole moment is doubled by keeping the current constant, the magnetic field at the centre of the loop is

B_{2}

. The ratio

\frac{B_{1}}{B_{2}}

is:

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

The ratio of the magnetic field at the centre of a current-carrying circular coil to magnetic moment is $x$ . If the current and the radius both are doubled. The new ratio will become

MEDIUM

Science>Physics>Magnetic Effect of Electric Current>Magnet

A coil in the shape of an equilateral triangle of side

l

is suspended between the pole pieces of a permanent magnet such that

B

is in plane of the coil. If due to a current

i

in the triangle, a torque

τ

rests on it, the side

l

of the triangle is

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

A bar magnet of magnetic moment

5 A m^{2}

is placed in a uniform magnetic induction

3 \times 10^{- 5} T .

If each pole of a magnet experiences a force of

2.5 \times 10^{- 4} N

then the magnetic length of the magnet is

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

Two particles, each of mass

m

and charge

q

are attached to the two ends of a light rigid rod of length

2 R

. The rod is rotated at constant angular speed about a perpendicular axis passing through its centre. The ratio of the magnitudes of the magnetic moment of the system and its angular momentum about the centre of the rod is

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

Magnetic moment of revolving electron of charge

e

and mass

m

in terms of angular momentum

L

of electron is

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

Torque acting on a rectangular coil carrying current

i

situated parallel to magnetic field of induction

B

, having the number of turns

n

and area

A

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

A magnetic dipole is acted upon by two magnetic fields which are inclined to each other at an angle of

75^{o}

. One of the fields has a magnitude of

15 mT

. The dipole attains stable equilibrium at an angle of

30^{o}

with this field. The magnitude of the other field (in

mT

) is close to

EASY

Science>Physics>Magnetic Effect of Electric Current>Magnet

The magnetic moment of electron due to orbital motion is proportional to (

n

= principal quantum numbers)

A circular loop and a square loop are formed from two wires of same length and cross section. Same current is passed through them. Then the ratio of their dipole moments is

Important Questions on Magnetic Effect of Electric Current

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