Magnetism and Matter MCQ Quiz - Multiple Choice Questions & Answers Page 4

31. 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

1. always zero
2. positive, negative or zero
3. unbounded
4. always negative

32. 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

1. is always zero.
2. can be zero at specific points.
3. cannot be positive or negative.
4. is not bounded.

33. In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is :

1. exponential
2. linear
3. algebraic
4. logarithmic

34. In a bar magnet, magnetic lines of force z :

1. are produced only at north pole like rays of light from a bulb
2. starts from north pole and ends at the south pole
3. emerge in circular paths from the middle of the bar
4. run continuously through the bar and outside

35. Ferrites may be:

1. ant. ferromagnetic
2. ferromagnetic
3. ferrimagnetic
4. None of the above

36. Curie temperature is the temperature above which

1. a ferromagnetic material becomes paramagnetic.
2. a ferromagnetic material becomes diamagnetic.
3. a paramagnetic material becomes diamagnetic.
4. a paramagnetic material becomes ferromagnetic.

37. Curie law xT = constant, relating magnetic susceptibility (x) and absolute temperature (T) of magnetic substance is obeyed by

1. all magnetic substances.
2. paramagnetic substances.
3. diamagnetic substances.
4. ferromagnetic substances.

38. At a given place on earth's surface the horizontal component of earth's magnetic field is 2 × 10^3-5 T and resultant magnetic field is 4 × 10^3-5 T. The angle of dip at this place is

1. 30^o
2. 60^o
3. 90^o
4. 45^o

39. A wire of length I has a magnetic moment M. It is then bent into a semi-circular arc. The new magnetic moment is :

1. M
2. M.l.
3. 2Mπ
4. Mπ

40. A magnetic needle is kept in a non-uniform magnetic field. It experiences

1. a torque but not a force.
2. neither a force nor a torque.
3. a force and a torque.
4. a force but not a torque.