MCQs on Magnetism
Question: For which of the following is magnetic susceptibility negative?
- Paramagnetic and Ferromagnetic materials
- Paramagnetic Materials only
- Ferromagnetic Materials only
- Diamagnetic Materials
Answer: (d) Diamagnetic Materials
Question: Which of the following is the unit of magnetic flux density?
- All of the above
Question: The magnetism of a magnet is due to
- cosmic rays
- due to pressure of big magnet inside the earth
- spin motion of electrons
Answer: (d) spin motion of electrons
Question: The magnetic field at a point x on the axis of a mall bar magnet is equal to the field at a point y on the equator of the same magnet. The ratio of the distances of x and y from the centre of the magnet is
Answer: (b) 21/3
Question: Which of the following materials is the most suitable for making a permanent magnet?
- Soft Iron
Answer: (d) Steel
Question: A sensitive magnetic field instrument can be effectively shielded from the external magnetic field by placing it inside which of the following materials?
- Plastic Material
- Teak Wood
- Soft Iron of high permeability
- A metal of high conductivity
Answer: (c) Soft Iron of high permeability
Question: A long magnet is cut into two parts such that the ratio of their lengths is 2:1. What is the ratio pole strength of both the section?
Answer: (d) Equal
Question: Which of the following statements is true about magnetic field intensity?
- Magnetic field intensity is the number of lines of force crossing per unit volume.
- Magnetic field intensity is the number of lines of force crossing per unit area.
- Magnetic field intensity is the magnetic induction force acting on a unit magnetic pole.
- Magnetic field intensity is the magnetic moment per unit volume.
Answer: (c) Magnetic field intensity is the magnetic induction force acting on a unit magnetic pole
Question: What happens to the magnetic needle kept in a non-uniform magnetic field?
- It experiences force but not torque
- It experiences torque but not force
- It experiences both force and torque
- It neither experiences force nor torque
Answer: (a) It experiences force but not torque
Question: What is the torque acting on the bar magnet of moment M which is placed in a uniform field H making an angle of 300 with the field?
Answer: (b) MH/2
Question: What happens to the magnetic moment if a hole is made at the centre of a bar magnet?
- Not a change
- None of the above
Answer: (c) Not a change
Question: Which of the following statements is true about magnetic lines of force?
- Magnetic lines of force are always closed.
- Magnetic lines of force always intersect each other.
- Magnetic lines of force tend to crowd far away from the poles of the magnet
- Magnetic lines of force do not pass through the vacuum.
Answer: (a) Magnetic lines of force are always closed.
Question: What is the work done by the magnet of moment M if it is rotated through 3600 in magnetic field H?
Answer: (d) Zero
Question: Magnetic lines of force of a bar magnet do not intersect because
- The lines have similar charges hence they repel each other
- The lines always diverge from a single point
- A point always has a single net magnetic field
- The lines need magnetic lenses to intersect
Answer: (c) A point always has a single net magnetic field