NEET Magnetism and Matter — Set 4

Question 1

A bar magnet with original $ m = 3.0 \, \text{A m}^2 $ is cut along its length into two equal parts. What is $ m $ of each part?

Accepted Answer

When cut along its length, each part typically has half the original magnetic moment in standard problems. Given: $ m = 3.0 \, \text{A m}^2 $. Each part: $ m' = \frac{3.0}{2} = 1.5 \, \text{A m}^2 $.

Question 2

The magnetic field lines of a bar magnet are closest together:

Accepted Answer

Magnetic field lines are closest together near the poles of a bar magnet, where the field strength is greatest, as the density of lines reflects the magnitude of the magnetic field.

Question 3

Which material exhibits perfect diamagnetism with $ \chi = -1 $ and is used in levitating trains?

Accepted Answer

Superconductors exhibit perfect diamagnetism with $ \chi = -1 $ due to the Meissner effect and are used in applications like magnetically levitated trains.

NEET Physics: Magnetism and Matter — Practice Set 4

Q1. A bar magnet with original \( m = 3.0 \, \text{A m}^2 \) is cut along its length into two equal parts. What is \( m \) of each part?

Q2. The magnetic field lines of a bar magnet are closest together:

Q3. Which material exhibits perfect diamagnetism with \( \chi = -1 \) and is used in levitating trains?

Q4. The magnetic field contribution \( B_m \) due to a material with \( M = 2.5 \times 10^5 \, \text{A m}^{-1} \) is: (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q5. A magnetic dipole of moment \( 0.3 \, \text{A m}^2 \) is in a uniform field of \( 0.7 \, \text{T} \) at \( 30^\circ \). What is the torque on it?

Q6. The magnetic field lines of a solenoid resemble those of a bar magnet because:

Q7. A material placed in a magnetic field reduces the field inside it slightly due to:

Q8. A solenoid with 800 turns per meter and current \( 1.5 \, \text{A} \) has a core with \( \mu_r = 300 \). What is \( B \) inside? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q9. A magnetic dipole experiences a torque of \( 0.02 \, \text{N m} \) in a field of \( 0.4 \, \text{T} \) at \( 90^\circ \). What is its magnetic moment?

Q10. A material with \( \mu_r = 250 \) and \( H = 700 \, \text{A m}^{-1} \) has \( B \): (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).