Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 15

MEDIUM

JEE Main

IMPORTANT

Earn 100

A bar magnet of length $l$ and magnetic dipole moment $M$ is bent in the form of an are as shown in the figure. The new magnetic dipole moment will be

75% studentsanswered this correctly

Important Questions on Magnetic Effects of Current and Magnetism

EASY

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 16

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

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 17

A triangular loop of side $l$ carries a current $I$ . It is placed in a magnetic field $B$ such that the plane of the loop is in the direction of $B$ . The torque on the loop is

HARD

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 18

A moving coil galvanometer has

150

equal divisions. Its current sensitivity is

10

divisions per

mA

and voltage sensitivity is

2

divisions per

mV

. In order that each division reads

1

V

, the resistance, in

ohms

, needed to be connected in series with the coil, will be

MEDIUM

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 19

A bar magnet has coercivity

4 \times 10^{3} A m^{- 1}

. It is desired to demagnetize it by inserting it inside a solenoid

12 cm

long and having

60

turns. The current that should be sent through the solenoid is

MEDIUM

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 20

An iron rod

0.2 m

long,

10^{- 2} m

in diameter and of permeability

1000

is placed inside a long solenoid, wound with

300

turns per

metre

. If a current of

0.5 A

is passed through the rod, find the magnetic moment of the rod.

HARD

JEE Main

IMPORTANT

Physics Crash Course JEE Main>Chapter 15 - Magnetic Effects of Current and Magnetism>Level 3>Q 21

Which of the following statements is not true?