NEET Magnetism and Matter — Set 8

Question 1

A material with $ \mu_r = 400 $ and $ H = 500 \, \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 = 400 $, $ H = 500 \, \text{A m}^{-1} $, $ \mu_0 = 4\pi \times 10^{-7} $. $ B = 4\pi \times 10^{-7} \times 400 \times 500 = 0.2512 \, \text{T} \approx 0.25 \, \text{T} $.

Question 2

Which property of magnetic field lines distinguishes them from electric field lines in the context of a dipole?

Accepted Answer

Magnetic field lines form continuous closed loops because there are no magnetic monopoles; they emerge from the north pole and enter the south pole, looping back internally. In contrast, electric field lines of a dipole start at the positive charge and end at the negative charge, or extend to infinity if unterminated.

Question 3

If a bar magnet is broken into two pieces, each piece retains both a north and a south pole. This observation supports the idea that:

Accepted Answer

Unlike electric charges, magnetic poles cannot be isolated. Breaking a magnet creates two smaller magnets, each with its own north and south pole, indicating that magnetic monopoles do not exist in nature, a key principle in magnetism.

NEET Physics: Magnetism and Matter — Practice Set 8

Q1. A material with \( \mu_r = 400 \) and \( H = 500 \, \text{A m}^{-1} \) has \( B \): (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q2. Which property of magnetic field lines distinguishes them from electric field lines in the context of a dipole?

Q3. If a bar magnet is broken into two pieces, each piece retains both a north and a south pole. This observation supports the idea that:

Q4. A material with \( B = 0.25 \, \text{T} \) and \( H = 1500 \, \text{A m}^{-1} \) has \( M \): (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q5. A bar magnet with \( m = 1.5 \, \text{A m}^2 \) produces a field at \( 0.5 \, \text{m} \) on its equatorial line. What is \( B \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q6. A bar magnet with magnetic moment \( 1.8 \, \text{A m}^2 \) is placed at a distance of \( 0.5 \, \text{m} \) along its axis. What is the magnetic field \( B \) at that point? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q7. A material has \( B = 0.3 \, \text{T} \) and \( M = 1.5 \times 10^5 \, \text{A m}^{-1} \). What is \( H \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q8. A material placed in a magnetic field increases the field inside it slightly and moves toward stronger field regions. This behavior is characteristic of:

Q9. A material with \( \mu_r = 150 \) and \( H = 800 \, \text{A m}^{-1} \) has \( B \): (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q10. The reason magnetic field lines are denser near the poles of a magnet is: