NEET Magnetism and Matter — Set 16

Question 1

A solenoid with 800 turns per meter carries a current of $ 2.5 \, \text{A} $. What is the magnetic intensity $ H $ inside?

Accepted Answer

Magnetic intensity $ H = n I $. Given: $ n = 800 \, \text{m}^{-1} $, $ I = 2.5 \, \text{A} $. Substitute: $ H = 800 \times 2.5 = 2000 \, \text{A m}^{-1} $.

Question 2

A material’s magnetic susceptibility becomes zero when:

Accepted Answer

For a superconductor below its critical temperature, the susceptibility $ \chi = -1 $ and relative permeability $ \mu_r = 0 $, but in a broader context, susceptibility can approach zero for non-magnetic materials or when magnetization is negligible compared to the applied field. However, the question implies a specific state, and superconductors achieve this uniquely with perfect diamagnetism.

Question 3

The magnetic field contribution $ B_m $ due to a material with $ M = 1.8 \times 10^5 \, \text{A m}^{-1} $ is: (Take $ \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} $).

Accepted Answer

$ B_m = \mu_0 M $. Given: $ M = 1.8 \times 10^5 \, \text{A m}^{-1} $, $ \mu_0 = 4\pi \times 10^{-7} $. $ B_m = 4\pi \times 10^{-7} \times 1.8 \times 10^5 = 0.22608 \, \text{T} \approx 0.23 \, \text{T} $.

NEET Physics: Magnetism and Matter — Practice Set 16

Q1. A solenoid with 800 turns per meter carries a current of \( 2.5 \, \text{A} \). What is the magnetic intensity \( H \) inside?

Q2. A material’s magnetic susceptibility becomes zero when:

Q3. The magnetic field contribution \( B_m \) due to a material with \( M = 1.8 \times 10^5 \, \text{A m}^{-1} \) is: (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q4. The potential energy of a magnetic dipole in a uniform field is highest when:

Q5. A bar magnet with \( m = 0.9 \, \text{A m}^2 \) is at \( 0.2 \, \text{m} \) along its axis. What is \( B \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q6. A material with \( \mu_r = 0 \) completely expels magnetic fields and is classified as:

Q7. The absence of a net force on a magnetic dipole in a uniform field implies:

Q8. A material has \( B = 0.42 \, \text{T} \) and \( M = 3.0 \times 10^5 \, \text{A m}^{-1} \). What is \( H \)? (Take \( \mu_0 = 4\pi \times 10^{-7} \, \text{T m A}^{-1} \)).

Q9. A material with susceptibility \( \chi = -5 \times 10^{-5} \) has a relative permeability \( \mu_r \) of:

Q10. The net magnetic flux through a closed surface around a toroid is: