MCQ Questions for Class 12 Physics Chapter 5 Magnetism and Matter with Answers
Question 1. S.I. unit of flux is :
(a) Ohm
(b) Weber
(c) Tesla
(d) None
Answer: (b) Weber
Question 2. Ferrites may be:
(a) ant. ferromagnetic
(b) ferromagnetic
(c) ferrimagnetic
(d) None of the above
Answer: (b) ferromagnetic
Question 3. In a permanent magnet at room temperature
(a) magnetic moment of each molecule is zero.
(b) the individual molecules have non-zero magnetic moment which are all perfectly aligned.
(c) domains are partially aligned.
(d) domains are all perfectly aligned
Answer: (c) domains are partially aligned.
Question 4. What is the angle of dip at a place where the horizontal component of earth’s magnetic field is equal to the vertical component?
(a) 0°
(b) 30°
(c) 45°
(d) 90°
Answer: (c) 45°
Question 5. Tangent law is applicable only when:
(i) two uniform and mutually perpendicular magnetic fields exist
(ii) two magnetic fields exist
(iii) horizontal component of earth’s magnetic field is present
(iv) uniform magnetic field are used
Answer: (i) two uniform and mutually perpendicular magnetic fields exist
Question 6. Which of the following has a low value in ferrites?
(a) Conductivity
(b) Permeability
(c) Magnetic susceptibility
(d) All the above
Answer: (a) Conductivity
Question 7. The earth behaves as a magnet with magnetic field pointing approximately from the geographic
(a) North to South
(b) South to North
(c) East to West
(d) West to East
Answer: (b) South to North
Question 8. The strength of the earth’s magnetic field is
(a) constant everywhere.
(b) zero everywhere.
(c) having very high value.
(d) vary from place to place on the earths surface.
Answer: (d) vary from place to place on the earths surface.
Question 9. The magnetic lines of force inside a bar magnet:
(a) do not exist
(b) depends on area of cross-section of bar magnet
(c) are from N-pole to S-pole of the magnet
(d) are from S-pole to N-pole of the magnet.
Answer: (d) are from S-pole to N-pole of the magnet.
Question 10. The dimensional representation of magnetic flux density is :
(a) [MLT-2]
(b) [MLT-2A-1]
(c) [MLT-2A-2]
(d) [MT-2A-1]
Answer: (d) [MT-2A-1]
Question 11. A magnetic bar of M magnetic moment is placed m the field of magnetic strength B, the torque acting on it is :
(a) M .B
(b) –M.B
(c) M×B
(d) B× M
Answer: (c) M×B
Question 12. A magnetic dipole moment is a vector quantity directed from:
(a) S to N
(b) N to S
(c) E to W
(d) W to E
Answer: (a) S to N
Question 13. S is the surface of a lump of magnetic material.
(a) Lines of B are not necessarily continuous across S.
(b) Some lines of B must be discontinuous across S.
(c) Lines of H are necessarily continuous across S.
(d) Lines of H cannot all be continuous across S.
Answer: (d) Lines of H cannot all be continuous across S.
Question 14. Which of the following is responsible for the earth’s magnetic field?
(а) Convective currents in earth’s core
(б) Diversive current in earth’s core.
(c) Rotational motion of earth.
(d) Translational motion of earth.
Answer: (а) Convective currents in earth’s core
Question 15.The magnetic susceptibility is negative for:
(i) diamagnetic material only
(ii) paramagnetic material only
(iii) ferromagnetic material only
(iv) paramagnetic and ferromagnetic materials
Answer: (i) diamagnetic material only
Question 16. Which of the following is a natural magnet?
(i) Magnetic needle
(ii) Bar magnet
(iii) Magnetite
(iv) Horseshoe magnet
Answer: (iii) Magnetite
Question 17. A current carrying power line carries current from west to east. What will be direction of magnetic field 1 meter above it?
(a) N to S
(b) S to N
(c) E to W
(d) W to E
Answer: (a) N to S
Question 18. Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator is
(i) always zero
(ii) positive, negative or zero
(iii) unbounded
(iv) always negative
Answer: (ii) positive, negative or zero
Question 19. If the magnetising field on a ferromagnetic material is increased, its permeability.
(i) is decreased
(ii) is increased
(iii) is unaffected
(iv) may be increased or decreased.
Answer: (i) is decreased
Question 20. The primary origin(s) of magnetism lies in
(a) Pauli exclusion principle.
(b) polar nature of molecules.
(c) intrinsic spin of electron.
(d) None of these.
Answer: (c) intrinsic spin of electron.
Question 21. What is the magnetic field in the empty space enclosed by the toroidal solenoid of radius ‘R’?
(a) Infinity
(b) µ04π.2π𝑙𝑅
(c) µ04π.(π𝑙𝑅)
(d) zero
Answer: (d) zero
Question 22. The dimensional representation of √l/MB is similar to that of:
(a) frequency
(b) time
(c) distance
(d) speed
Answer: (b) time
Question 23. Which of the following independent quantities is not used to specify the earth’s magnetic field?
(a) Magnetic declination (θ).
(b) Magnetic dip (δ).
(c) Horizontal component of earth’s field (BH).
(d) Vertical component of earth’s field (BV).
Answer: (d) Vertical component of earth’s field (BV).
Question 24. The vertical component of earth’s magnetic field at a place is √3 times the horizontal component the value of angle of dip at this place is
(a) 30°
(b) 45°
(c) 60°
(d) 90°
Answer: (c) 60°
Question 25. At a given place on earth’s surface the horizontal component of earth’s magnetic field is 2 × 10-5 T and resultant magnetic field is 4 × 10-5 T. The angle of dip at this place is
(a) 30°
(b) 60°
(c) 90°
(d) 45°
Answer: (b) 60°
Question 26. Which of the following property shows the property of ferromagnetic substances?
(a) The ferromagnetic property depends on temperature.
(b) The ferromagnetic property does not depend on temperature.
(c) At high enough temperature ferromagnet becomes a diamagnet.
(d) At low temperature ferromagnet becomes a paramagnet.
Answer: (a) The ferromagnetic property depends on temperature.
Question 27. Magnetic moment for solenoid and corresponding bar magnet is
(a) equal for both
(b) more for solenoid
(c) more for bar magnet
(d) none of these
Answer: (a) equal for both
Question 28. The magnetic field strength due to a short bar magnet directed along its axial line at a distance r is B. What is its value at the same distance along the equatorial line?
(a) B
(b) 2B
(c) B/2
(d) B/4
Answer: (c) B/2