NEET Physics: Magnetism questions with solutions

Q1. Which of the following is not a property of magnetic lines of force?

1. They neither have origin nor end.
2. These lines do not intersect
3. outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
4. None

Answer: None

Magnetic field lines form closed loops, never intersect, and outside a magnet go from north to south while inside they return from south to north. Since A, B, and C are all correct properties, the only choice that fits is “None.”

Q2. Magnetic field lines:

1. starts from north pole
2. starts from south pole
3. starts from current-carrying wires
4. are closed loops

Answer: are closed loops

Magnetic field lines form continuous closed loops because isolated magnetic poles do not exist. Outside a magnet they go from north to south, and inside the magnet they return from south to north, completing the loop.

Q3. The B-H curve (i) and (ii) shown in fig., associated with

1. (i) diamagnetic and (ii) paramagnetic substance
2. (i) paramagnetic and (ii) ferromagnetic substance
3. (i) soft iron and (ii) steel respectively
4. (i) steel and (ii) soft iron respectively

Answer: (i) paramagnetic and (ii) ferromagnetic substance

A paramagnetic substance has a small positive susceptibility, so its B-H curve rises only slightly and almost linearly. A ferromagnetic substance magnetizes much more strongly, giving a steep, nonlinear curve with saturation, which matches the second curve.

Q4. are used in making electric generators and electric motors.

1. electric current
2. magnetes
3. cables
4. all

Answer: magnetes

Magnets are essential in electric generators and motors because they provide the magnetic field needed for electromagnetic induction and motor action. Electric current and cables are used in the devices, but they are not the specific material being asked for.

Q5. Which of the following materials is best suited as the core of an electromagnet

1. steel
2. Iron
3. Alnico
4. Magnetite

Answer: Iron

Iron is best because it becomes strongly magnetized in a current-carrying coil and demagnetizes readily when the current stops. That makes it ideal for an electromagnet core, unlike steel or Alnico, which retain magnetism more strongly.

Q6. Assertion To protect any instrument from external magnetic field, it is put inside an iron body. Reason Iron is a magnetic substance.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Answer: Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

The assertion is true because iron can shield an instrument by offering an easier path for magnetic field lines, reducing the field inside. The reason is also true, but simply saying iron is magnetic does not explain why it protects; the shielding effect is the real reason.

Q7. Two proton beams are moving in the parallel direction. Which of the following statements are correct. This question has multiple correct options

1. Force between the proton beams will be attractive
2. Magnetic force between proton beams will be attractive
3. Repulsive force will be greater than attractive forces
4. Magnetic and electrostatic forces will cancel each other

Answer: Repulsive force will be greater than attractive forces

Two proton beams repel electrically because like charges repel. Since they move in the same direction, each beam also creates a magnetic field that attracts the other beam, but this magnetic attraction is weaker than the electrostatic repulsion, so the net force remains repulsive.