Physics Chapter 6 Entry test MCQs
Topic 6
Electrostatics
1. Two charges IC and -4C exists in air. What is the direction of force?
a. From IC to-4C
b. Away from IC
c. From-4C to IC
d. Away from-4C
2. A point charge 2nC is located at origin. What is the potential at (1,0,0)?
a. 16
b. 12
c. 18
d. 14
3. A point charge 0.4nC is located at (2, 3, 3). Find the potential differences between (2, 3, 3) m and (-2, 3, 3) m due to the charge.
a. 2.7
b. 2.5
c. 2.8
d. 2.6
4. What is the dielectric constant of the medium if the capacitance of a parallel plate capacitor increases from 40F to 80F on introducing a dielectric medium between the plates?
a. 2
b. 20
c. 5
d. 0.5
5. What is the maximum energy that can be stored in a capacitor?
a. Depends on the maximum electric field
b. Depends on the maximum area of the capacitor
c. Depends on the maximum current passing through the capacitor
d. Depends on the maximum resistance offered
6. What is the voltage across the 2F capacitor?
a. 240V
b. 200V
c. 220V
d. 120V
7. What is the initial current while charging a capacitor?
a. 0
b. High
c. Cannot be determined
d. Low
8. Calculate the total charge of the system
a. 200C
b. 100C
c. 300C
d. 400C
9. If the distance between two-point charges to becomes double then the coulomb’s force will be
a. 2F
b. F/2
c. F/4
d. 4F
10. The force between two-point charges placed in air is F. If air is replaced by a medium of relative permittivity εr the force is reduced to
a. εrF
b. εr/F
c. F/εr
d. εr
11. Two identical metal balls with charges + 2Q and-Q are separated by some distance, and exert a force Fon each other. They are joined by a conducting wire, which is then removed. The force between them will now be.
a. F/4
b. F
c. F/8
d. F/2
12. When 1019 electrons are removed from a neutral metal plate, the electric charge on it is in (coulomb)
a. +1.6
b. 10+19
c. 10-19
d. -1.6
13. Two point charges +3µC and +8µC repel each other with a force of 40N. If a charge of -5µC is added to each of the, then the force between them will become:
a. +10 N
b. 10 N
c. -20 N
d. +20 N
14. Two point charges +2 C and +6 C repel each other with a force of 12 N. If a charge of -2 C is given to each of these charges, the force will now be
a. 8 N (attractive)
b. Zero
c. 16 N (attractive)
d. 8 N (repulsive)
15. Two electrons are removed from a conductor the charge on it is
a. 3.2 x 10-19C
b. 1.6 x 10-19C
c. neutral
d. 3.2 x 10-19C
16. The force between two charges is 120 N. If the distance between the charges is doubled, the force will be
a. 30 N
b. 60 N
c. 15 N
d. 40 N
17. A positive charge is moved against an electric field. Its P.E
a. Decreases
b. Increases
c. May increase or decrease depending upon magnitude of charge
d. Remains same
18. An electric field can deflect———-.
a. y-rays
b. Neutrons
c. X-rays
d. None
19. Which of given is not the unit of electric intensity
a. Vm-1
b. NV-1
c. NC-1
d. None of these
20. The magnitude of electric intensity E is such that an electron placed in it would experience an electrical force equal to its weight. E is given by
a. c/(mg)
b. mge
c. (e2g)(m2)
d. (mg)e
21. The electric field intensity at a point 20 cm away from a charge of 2 x 105C is
a. 3.5 x 106N / C
b. 4.5 x 106N / C
c. 4.5 x 105N / C
d. 3.5 x 105N / C
22. The weight of proton (mass= 1.67 x 10-27 kg) on entering in a vertical electric field E is balanced by electric force. Then the electric field strength is
a. 107 Vm-1
b. 10-9Vm-1
c. 10-8Vm-1
d. 10-7Vm-1
23. 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
d. None of these
24. Two metal plates potential difference of 300 V and are 0.01 m apart. A charged particle of mass 1.96 x 10-15 kg is held in equilibrium between the plates of the capacitor. Then the electric field is
a. 3×102 Vm-1
b. 3×104 Vm-1
c. 3Vm-1
d. 3×10-4 Vm-1
25. The electric field strength between a pair of parallel plates is E. The separation of the plates is doubled and the potential difference between the plates is increased by a factor of four. What is the new electric field strength?
a. 2 E
b. E
c. 8 E
d. 4 E