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Free download in PDF Class 12 Physics Chapter 4 Moving Charges and Magnetism Multiple Choice Questions and Answers for Board, JEE, NEET, AIIMS, JIPMER, IIT-JEE, AIEE and other competitive exams. MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. These short solved questions or quizzes are provided by Gkseries. These will help the students for preparation of their examination./p>
(1)
The radius of the trajectory of a charged particle in a uniform magnetic field is proportional to the:
[A]
charge on the particle
[B]
energy of the particle
[C]
momentum of the particle
[D]
all the above
Answer: momentum of the particle
(2)
10 eV electron is circulating in a plane at right angle to a uniform field of magnetic induction 10-1 Wb/m² (1G). The orbital radius of electron is:
[A]
12 cm
[B]
16 cm
[C]
11 cm
[D]
18 cm
(3)
Earth’s magnetism was discovered by:
[A]
Gauss
[B]
Oersted
[C]
Ampere
[D]
Gilbert
(4)
Isoclinic lines are the lines joining places with :
[A]
equal dip
[B]
equal declination
[C]
equal dip and declination
[D]
None of these
(5)
When charged particle enters-a uniform magnetic field, its K.E.:
[A]
remains constant
[B]
increases
[C]
decreases
[D]
becomes zero
(6)
Which of the following is not a unit of magnetic induction?
[A]
gauss
[B]
tesla
[C]
oersted
[D]
weber/metre²
(7)
A current carrying power line carries current from west to east. Then the direction of the magnetic field 2 m above it is :
[A]
west to east
[B]
south to north
[C]
north to south
[D]
None of these
(8)
What happens to the magnetic field at the centre of a circular current carrying coil if we double the radius of the coil keeping the current unchanged?
[A]
halved
[B]
doubled
[C]
quadrupled
[D]
remains unchanged
(9)
What is the angle of dip at the magnetic poles ?
[A]
30°
[B]
0°
[C]
45°
[D]
None of these
(10)
A wire of length 2 metre carries a current 1 ampere, is bent to form a circle. The magnetic moment of the coil is :
[A]
2π
[B]
π/2
[C]
π/4
[D]
1/π
(11)
The force between two parallel current carrying conductors is F. If the current in each conductor is doubled, then the force between them becomes :
[A]
4F
[B]
2F
[C]
F
[D]
F/4
(12)
The strength of the magnetic field around an infinite current carrying conductor is :
[A]
same everywhere
[B]
inversely proportional to the distance
[C]
directly proportional to the distance
[D]
None of these
Answer: inversely proportional to the distance
(13)
To convert galvanometer into voltmeter one should connect :
[A]
high resistance in series with galvanometer
[B]
low resistance in series with galvanometer
[C]
high resistance in parallel with galvanometer
[D]
low resistance in parallel with galvanometer
Answer: high resistance in series with galvanometer
(14)
The magnetic field of a given length of a ware for single turn coil at its centre is B. Then.its value for two turns of coil will be :
[A]
B/4
[B]
B/2
[C]
4B
[D]
2B
(15)
The magnetic field produced by an / meter long straight (x cry thin) current (I) carry ing conductor at any point on itself is :
[A]
zero
[B]
infinite
[C]
µ0l/4πl
[D]
µ0l/2πl
(16)
When we double the radius of a coil keeping the current through it unchanged, what happens to the magnetic field directed along its axis at far off points?
[A]
halved
[B]
doubled
[C]
quadrupled
[D]
remains unchanged
Answer: remains unchanged
(17)
According to Gauss’s theorem in magnetism, surface integral of magnetic field intensity over a surface (closed or open) is always:
[A]
-1
[B]
1
[C]
0
[D]
infinity
(18)
The sensitivity of a tangent galvanometer can be increased by increasing:
[A]
the radius of the coil
[B]
the external magnetic field
[C]
the number of turns of the coil
[D]
all the above
Answer: the external magnetic field
(19)
Which of the following shows that the earth behaves as a magnet?
[A]
Repulsion between like poles .
[B]
Attraction between unlike poles
[C]
Null points in the magnetic field of a bar magnet
[D]
No existence of isolated magnetic poles
Answer: Null points in the magnetic field of a bar magnet
(20)
Circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is :
[A]
1.57 × 10-3Wb/m²
[B]
8.0 × 10-5 Wb/m²
[C]
2.0 × 10-3 Wb/m²
[D]
3.l4 × 10-1 Wb/m²
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