NCERT Class 12 MCQ Quiz Hub

1. S.I. unit of flux is :
Ohm
Weber
Tesla
None

2. What is the angle of dip at a place where the horizontal component of earth’s magnetic field is equal to the vertical component?
0°
30°
45°
90°

3. Which of the following has a low value in ferrites?
Conductivity
Permeability
Magnetic susceptibility
All the above

4. The dimensional representation of magnetic flux density is :
[MLT-2]
[MLT-2A-1]
[MLT-2A-2]
[MT-2A-1]

5. Tangent law is applicable only when:
two uniform and mutually perpendicular magnetic fields exist
two magnetic fields exist
horizontal component of earth’s magnetic field is present
uniform magnetic field are used

6. Ferrites may be:
ant. ferromagnetic
ferromagnetic
ferrimagnetic
None of the above

7. The magnetic lines of force inside a bar magnet:
do not exist
depends on area of cross-section of bar magnet
are from N-pole to S-pole of the magnet
are from S-pole to N-pole of the magnet.

8. A magnetic dipole moment is a vector quantity directed from:
S to N
N to S
E to W
W to E

9. The dimensional representation of l/MB−−−−−√ is similar to that of:
frequency
time
distance
speed

10. A current carrying power line carries current from west to east. What will be direction of magnetic field 1 meter above it?
N to S
S to N
E to W
W to E

11. On quadrupling the moment of inertia of a magnet, its frequency of oscillation will become:
half
double
four times
one-fourth

12. 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?
B
2B
B/2
B/4

13. 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:
zero
more than that of earth
less than that of earth
equal to that of earth

14. In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is :
exponential
linear
algebraic
logarithmic

15. The force between two parallel wire 2 × 10-7 Nm-1, placed 1 m apart to each other in vacuum. The electric current flowing through the wires is:
1 A
zero
5 × 106 A
2 × 10-7 A

16. Which of the following has higher magnetic susceptibility?
diamagnetic
paramagnetic
ferromagnetic
None of the above

17. The magnetic field of earth is due to:
induction effect of the sun
the presence of a large magnet at the centre of the earth
interaction of cosmic rays with the current of earth
motion and distribution of some material in an outside the earth

18. In a bar magnet, magnetic lines of force z :
are produced only at north pole like rays of light from a bulb
starts from north pole and ends at the south pole
emerge in circular paths from the middle of the bar
run continuously through the bar and outside

19. The Mariner’s compass is provided with Gimbals arrangement so as to :
keep the needle always horizontal
give a direct reading of declination
give the direct value of dip
All the above

20. A wire of length I has a magnetic moment M. It is then bent into a semi-circular arc. The neyv magnetic moment is :
M
M.l.
2M/π
M/π

21. The radius of curvature of the path of charged particle in a uniform magnetic file is directly proportional to the
charge on fie particle
Momentum of particle
energy of particle
Strength of field

22. 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:
B/2
B/4
2B
4B