Magnetism and Matter Past Year Questions (PYQs)

Please note that the Standard symbols are used with their conventional meanings. ‘^’ denotes raised to the power. The answers are provided at the end of this article. All questions adhere to the NCERT syllabus and hold significance for the NEET-UG examination. Additional hints are included where necessary. This serves as a practice test, hence ensure thorough revision before attempting the questions.

## Magnetism and Matter PYQs

**An iron rod with a susceptibility of 599 is exposed to a magnetizing field of 1200 A m-1. What is the permeability of the material of the rod?**

A) 8.0 * 10

**What are the relationships among the three elements of the earth’s magnetic field – horizontal component H, vertical component V, and dip δ – given a total magnetic field BE?**

A) V = B

**At a specific point on the earth’s surface, if the angle of dip δ = +25 degrees, what can be inferred?**

A) A and B are both situated in the northern hemisphere.

**When a 250-turn rectangular coil, measuring 2.1 cm in length and 1.25 cm in width, carries a current of 85 A and is exposed to a magnetic field of strength 0.85 T, what is the work done to rotate the coil by 180 degrees against the torque?**

A) 9.1 J

**If ‘be’ represents the apparent angle of dip observed in two vertical planes perpendicular to each other, what is the formula for determining the true angle of dip?**

A)

**A bar magnet is suspended in a uniform horizontal magnetic field via a thin cotton thread and is in equilibrium. What is the energy required to rotate it by 60 degrees? And what is the torque required to maintain the magnet in this new position?**

A) W/

**For which type of materials is the magnetic susceptibility negative?**

A) Diamagnetic material only

**Different configurations of bar magnets are depicted in the figures below. Each magnet possesses a magnetic dipole moment m. Which configuration yields the highest net magnetic dipole moment?**

A)

**When a bar magnet of length l and magnetic dipole moment M is bent into an arc, what will be the new magnetic dipole moment?**

A) 3

**If a compass needle, movable in a horizontal plane, is taken to a geomagnetic pole, what will happen to it?**

A) It will stay in any position.

**If a magnetic needle suspended parallel to a magnetic field requires J of work to turn it through 60 degrees, what torque is needed to maintain the needle in this position?**

A) 23 J

**When a bar magnet is brought near four lightweight rod samples, A, B, C, and D, the following observations are made:**

A) A is feebly repelled B) B is feebly attracted C) C is strongly attracted D) D remains unaffected

**Which inference is true?**

A) B is of paramagnetic material

**A short bar magnet with a magnetic moment of 0.4 JT-1 is positioned in a uniform magnetic field of 0.16 T. At what potential energy is the magnet in stable equilibrium?**

A) -0.082 J

**Why are electromagnets made of soft iron?**

A) Soft iron has high retentivity and low coercive force.

**A vibration magnetometer with a small bar magnet oscillates with a time period of 2 s in the earth’s horizontal magnetic field of 24 microtesla. What will be the new time period of the magnet when a horizontal field of 18 microtesla, opposite to the earth’s field, is produced by a current-carrying wire?**

A) 4 s

**A closely wound solenoid with 2000 turns and an area of cross-section 1.5 * 10-4 m2 carries a current of 2.0 A. When suspended through its center and perpendicular to its length, and placed in a uniform magnetic field of 5 * 10-2 tesla at an angle of 30 degrees, what is the torque on the solenoid?**

A) 3 * 10

**What is the magnetic moment of a diamagnetic atom?**

A) Equal to zero

**Two identical bar magnets are fixed with their centers at a distance d apart. A stationary charge Q is placed at P between the gap of the two magnets at a distance D from the center O. What is the force on the charge Q?**

A) Directed along OP

**A thin ring of radius R meter has charge q coulomb uniformly spread on it and rotates about its axis with a constant frequency of f revolution/s. What is the value of magnetic induction in Wb/m2 at the center of the ring?**

A)

**A bar magnet with a magnetic moment of 2 * 104 JT-1 is free to rotate in a horizontal plane. When a horizontal magnetic field B = 6 * 10-4 T exists in the space, what is the work done in taking the magnet slowly from a direction parallel to the field to a direction 60 degrees from the field?**

A) 12 J

## Answers:

- A
- A
- B
- A
- [Answer formula]
- A
- B
- [Corresponding figure]
- A
- D
- A
- B
- A
- A
- A
- A
- D
- B
- [Answer formula]
- A