EASY

Earn 100

Gyromagnetic ratio is the ratio of magnetic moment $μ$ to the orbital angular momentum $(l)$ . Its numerical value for an electron is given by.

Important Questions on Moving Charges and Magnetism

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

n

= principal quantum numbers)

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

A wire of length

L

metre carrying a current of

I

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

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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:

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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 :

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

The magnetic moment of an electron

(e)

revolving in an orbit around nucleus with an orbital angular momentum is given by

HARD

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

A proton is revolving on a circular path of radius

2 mm

with frequency

10 Hz

. Magnetic dipole moment associated with proton is

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

In a permanent magnet at room temperature

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

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:

MEDIUM

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

What is the magnetic moment of orbiting electron in simple hydrogen atom?
Assume

e =

charge of electron,

m_{e} =

mass of electron and

\vec{L} =

orbital angular momentum of electron

EASY

Physics>Electricity and Magnetism>Moving Charges and Magnetism>Torque on Current Loop, Magnetic Dipole

The ratio of angular momentum

L

to the atomic dipole moment

μ_{i}

for hydrogen like atoms and ions is

Gyromagnetic ratio is the ratio of magnetic moment μ to the orbital angular momentum l. Its numerical value for an electron is given by.

Important Questions on Moving Charges and Magnetism

Learn and Prepare for any exam you want !

Gyromagnetic ratio is the ratio of magnetic moment $μ$ to the orbital angular momentum $(l)$ . Its numerical value for an electron is given by.