NEET Magnetism and Matter — Set 14

Question 1

The net magnetic flux through a closed surface surrounding a current-carrying solenoid is:

Accepted Answer

Gauss’s law for magnetism states that the net magnetic flux through any closed surface is zero, as magnetic field lines form closed loops.

Question 2

A material with $ \mu_r = 500 $ and $ H = 300 \, \text{A m}^{-1} $ has $ B $: (Take $ \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} $).

Accepted Answer

$ B = \mu_0 \mu_r H $. Given: $ \mu_r = 500 $, $ H = 300 \, \text{A m}^{-1} $, $ \mu_0 = 4\pi \times 10^{-7} $. $ B = 4\pi \times 10^{-7} \times 500 \times 300 = 0.1884 \, \text{T} \approx 0.19 \, \text{T} $.

Question 3

A bar magnet with $ m = 2.2 \, \text{A m}^2 $ produces a field at $ 0.3 \, \text{m} $ on its equatorial line. What is $ B $? (Take $ \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} $).

Accepted Answer

$ B = \frac{\mu_0}{4\pi} \frac{m}{r^3} $. Given: $ m = 2.2 \, \text{A m}^2 $, $ r = 0.3 \, \text{m} $, $ \frac{\mu_0}{4\pi} = 10^{-7} $. $ B = 10^{-7} \times \frac{2.2}{(0.3)^3} = 10^{-7} \times \frac{2.2}{0.027} \approx 8.15 \times 10^{-6} \, \text{T} $.

NEET Physics: Magnetism and Matter — Practice Set 14

Q1. The net magnetic flux through a closed surface surrounding a current-carrying solenoid is:

Q2. A material with \( \mu_r = 500 \) and \( H = 300 \, \text{A m}^{-1} \) has \( B \): (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q3. A bar magnet with \( m = 2.2 \, \text{A m}^2 \) produces a field at \( 0.3 \, \text{m} \) on its equatorial line. What is \( B \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q4. A bar magnet with original \( m = 2.8 \, \text{A m}^2 \) is cut transversely into two equal parts. What is \( m \) of each part?

Q5. A solenoid with 500 turns per meter carries a current of \( 4.5 \, \text{A} \). What is the magnetic intensity \( H \) inside?

Q6. A bar magnet with \( m = 3.0 \, \text{A m}^2 \) is at \( 0.4 \, \text{m} \) along its axis. What is \( B \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q7. A dipole with \( m = 0.6 \, \text{A m}^2 \) in a field \( B = 0.8 \, \text{T} \) at \( 0^\circ \) has potential energy:

Q8. A material has \( B = 0.25 \, \text{T} \) and \( M = 1.8 \times 10^5 \, \text{A m}^{-1} \). What is \( H \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q9. In a material where magnetic domains spontaneously align over large regions, the susceptibility is:

Q10. A paramagnetic material with \( \chi = 9 \times 10^{-4} \) in \( H = 2000 \, \text{A m}^{-1} \) has magnetization \( M \):