COMEDK 2025 Evening Shift | Magnetism and Matter Question 1 | Physics

A short bar magnet placed with its axis at $45^{\circ}$ with an external field of $400 \times 10^{-4} \mathrm{~T}$ experiences a torque of 0.024 Nm . If a solenoid of cross-sectional area $10^{-4} \mathrm{~m}^2$ and 500 turns replaces the short bar magnet such that they have the same magnetic moment, then the current flowing through the solenoid is:

$2 \sqrt{2} \mathrm{~A}$

$5 \sqrt{2} \mathrm{~A}$

$12 \sqrt{2} \mathrm{~A}$

$4 \sqrt{2} \mathrm{~A}$

COMEDK 2025 Evening Shift

MCQ (Single Correct Answer)

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A metal rod of susceptibility 799 is subjected to a magnetising field of $2000 \mathrm{Am}^{-1}$. The permeability of the material of the rod is: (Given $\mu_0=4 \pi \times 10^{-7} \mathrm{TmA}^{-1}$ )

$4.2 \pi \times 10^{-7} T m A^{-1}$

$3.2 \pi \times 10^{-4} \mathrm{TmA}^{-1}$

$2.4 \pi \times 10^{-5} \mathrm{TmA}^{-1}$

$80 \pi \times 10^{-7} T m A^{-1}$

COMEDK 2025 Afternoon Shift

MCQ (Single Correct Answer)

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For a short magnet, the magnetic field on the axial line at a distance 10 cm from its centre is $1.6 \mathrm{~m} \times 10^{-7} \mathrm{~T}$. What is the magnetic field on its equatorial line at the same distance 10 cm from its centre?

$4.8 \times 10^{-7} T$

$3.2 \times 10^{-8} T$

$1.6 \times 10^{-7} T$

$0.8 \times 10^{-7} T$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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Which of the following is not a characteristic of diamagnetism?

The material moves from a region of strong magnetic field to weak magnetic field.

The origin of diamagnetism is the spin of electrons.

Their magnetic susceptibility is small and negative.

Diamagnetic materials are repelled by bar magnets.

COMEDK Subjects