Objective Type Question Answers On Class 12 Physics Chapter 5 Magnetism and Matter

1 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:are from S-pole to N-pole of the magnet.

2 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

View Answer

Answer:B/2

3 In a bar magnet, magnetic lines of force z :

A are produced only at north pole like rays of light from a bulb

B starts from north pole and ends at the south pole

C emerge in circular paths from the middle of the bar

D run continuously through the bar and outside

View Answer

Answer:starts from north pole and ends at the south pole

4 The relation between geometric length (L) and magnetic length (L_m) is:

A

B

C (a) L_m = L_g

D L_m = 2RY;UL L_g

View Answer

Answer:

5 The force acting per unit length of a semi circular wire of radius R carrying a current I is:

A

B

C

D

View Answer

Answer:

6 The neutral point in the magnetic field of a horizontally placed bar magnet is a point where the magnetic field due to that bar magnet is:

A zero

B more than that of earth

C less than that of earth

D equal to that of earth

View Answer

Answer:equal to that of earth

7 What is the magnetic field in the empty space enclosed by the toroidal solenoid of radius ‘R’? ,

A Infinity

B

C

D zero

View Answer

Answer:zero

8 Ferrites may be:

A ant. ferromagnetic

B ferromagnetic

C ferrimagnetic

D None of the above

View Answer

Answer:ferromagnetic

9 The magnetic field at the centre of a current carrying circular loop is B. If the radius of the loop is doubled keeping the current unchanged, the magnetic field at the centre of loop will become:

A B/2

B B/4

C 2B

D 4B

View Answer

Answer:B/4

10 A magnetic bar of M magnetic moment is placed m the field of magnetic strength B, the torque acting on it is :

A

B

C

D

View Answer

Answer:C

11 The dimensional representation of

is similar to that of:

A frequency

B time

C distance

D speed

View Answer

Answer:time

12 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°

View Answer

Answer:45°

13 S.I. unit of flux is :

A Ohm

B Weber

C Tesla

D None

View Answer

Answer:Weber

14 The dimensional representation of magnetic flux density is :

A [MLT^-2]

B [MLT^-2A^-1]

C [MLT^-2A^-2]

D [MT^-2A^-1]

View Answer

Answer:[MT^-2A^-1]

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

A exponential

B linear

C algebraic

D logarithmic

View Answer

Answer:linear

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

A M

B M.l.

C 2M/π

D M/π

View Answer

Answer:2M/π

17 Which of the following is not showing the essential difference between electrostatic shielding by a conducting shell and magnetostatic shielding?

A Electrostatic field lines can end on charges and conductors have free charges.

B Magnetic field lines can end but conductors cannot end them.

C Lines of magentic field cannot end on any material and perfect shielding is not possible.

D Shells of high permeability materials can be used to divert lines of magnetic field from the interior region.

View Answer

Answer:Magnetic field lines can end but conductors cannot end them.

18 Which of the following property shows the property of ferromagnetic substances?

A The ferromagnetic property depends on tem-perature. ‘

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.

View Answer

Answer:The ferromagnetic property depends on tem-perature.

19 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

A always zero

B positive, negative or zero

C unbounded

D always negative

View Answer