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Free download in PDF Class 12 Physics Chapter 2 Electrostatic Potential Capacitance and Fields 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)
What is the number of electrons in 100 g water?
[A]
3.35 × 1024
[B]
3.35 × 1025
[C]
6.02 × 1023
[D]
None of these
(2)
The electric potential of earth is taken as:
[A]
zero
[B]
infinity
[C]
unity
[D]
None of these
(3)
Which of the following statement is true?
[A]
Electrostatic force is a conservative force.
[B]
Potential at a point is the work done per unit charge in bringing a charge from any point to infinity.
[C]
Electrostatic force is non-conservative
[D]
Potential is the productof charge and work.
Answer: Electrostatic force is a conservative force.
(4)
A capacitor is charged by using a battery which is then disconnected. A dielectric slab
then slipped between the plates, which results in
[A]
reduction of charge on the plates and increase of potential difference across the plates.
[B]
increase in the potential difference across the plate, reduction in stored energy, but no change in the charge on the plates.
[C]
decrease in the potential difference across the plates, reduction in the stored energy, but no change in the charge on the plates.
[D]
none of these
Answer: decrease in the potential difference across the plates, reduction in the stored energy, but no change in the charge on the plates.
(5)
The work done in bringing a unit positive charge from infinite distance to a point at distance x from a positive charge Q is W. Then the potential at that point is
[A]
WQ/x
[B]
W
[C]
W/x
[D]
WQ
(6)
Acapacitor of 4 pF is connected as shown in the circuit. The internal resistance of the battery is 0.5
Q. The amount of charge on the capacitor plates will be
[A]
0
[B]
4
[C]
16 μC
[D]
8 μC
(7)
Two metal plates form a parallel plate capacitor. The distance between the plates is d. A metal sheet of thickness d/2 and of the same area is introduced between the plates.
What is the ratio of the capacitance in the two cases?
[A]
2 : 1
[B]
3 : 1
[C]
2 : 1
[D]
5 : 1
(8)
Three charges Q, +q and +q are placed at the vertices of an equilateral triangle of side l as shown in the figure. If the net electrostatic energy of the system is zero, then Q is equal to
[A]
-q
[B]
+q
[C]
zero
[D]
–q/2
(9)
A parallel plate condenser is connected with the terminals of a battery. The distance between the plates is 6mm. If a glass plate (dielectric constant K = 9) of 4.5 mm is introduced between them, then the capacity will become
[A]
2 times.
[B]
the same.
[C]
3 times.
[D]
4 times.
(10)
The radii of two metallic spheres A and B are r1 and r2 respectively (r1 > r2). They are connected by a thin wire and the system is given a certain charge. The charge will be greater
[A]
on the surface of the sphere B.
[B]
on the surface of the sphere A.
[C]
equal on both.
[D]
zero on both.
Answer: on the surface of the sphere A.
(11)
64 drops each having the capacity C and potential V are combined to form a big drop. If the charge on the small drop is q, then the charge on the big drop will be
[A]
2q
[B]
4q
[C]
16q
[D]
64q
(12)
Two small spheres each carrying a charge q are placed r metre apart. If one of the spheres is taken around the other one in a circular path of radius r, the work done will be equal to
[A]
force between them × r
[B]
force between them × 2πr
[C]
force between them/2πr
[D]
zero
(13)
If a unit positive charge is taken from one point to another over an equipotential surface, then
[A]
work is done on the charge.
[B]
work is done by the charge.
[C]
work done is constant.
[D]
no work is done.
(14)
The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is
[A]
proportional to the square root of the distance between the plates.
[B]
linearly proportional to the distance between the plates.
[C]
independent of the distance between the plates.
[D]
inversely proportional to the distance between the plates.
Answer: independent of the distance between the plates.
(15)
Which of the following options are correct? If a conductor has a potential V 4- 0 and there are no charges anywhere else outside, then
[A]
there must not be charges on the surface or inside itself.
[B]
there cannot be any charge in the body of the conductor.
[C]
there must be charges only on the surface.
[D]
there must be charges inside the surface.
Answer: there cannot be any charge in the body of the conductor.
(16)
Which of the following options is correct? In a region of constant potential
[A]
the electric field is uniform.
[B]
the electric field is zero.
[C]
there can be charge inside the regiofi.
[D]
the electric field shall necessarily change if a charge is placed outside the region.
Answer: the electric field is zero.
(17)
v Figure shows the electric lines of force emerging from a charged body. If the electric field at A and B are EA and EB respectively and if the displacement between A and B is r then
[A]
EA > EB
[B]
EA < EB
[C]
EA = EB/r
[D]
EA = EB /r²
(18)
A conductor with a positive charge
[A]
is always at +ve potential.
[B]
is always at zero potential.
[C]
is always at negative potential.
[D]
may be at +ve, zero or -ve potential.
Answer: may be at +ve, zero or -ve potential.
(19)
A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system
[A]
increases by a factor of 4.
[B]
decreases by a factor of 2.
[C]
remains the same.
[D]
increases by a factor of 2.
Answer: decreases by a factor of 2.
(20)
A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The potential at the centre of the sphere is
[A]
0 V
[B]
10 V
[C]
Same as at point 5 cm away from the surface
[D]
Same as at point 25 cm away from the surface
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