12 - Physics - Unit 1 - Electro Statics

15 Questions | By Padasalaiphysics | Updated: Mar 22, 2022 | Attempts: 13641

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Prepared by Mr. P. ILAIYARAJA M. Sc. ,B. Ed. , PG ASST IN PHYSICS , GHSS, PANCHANATHIKKULAM EAST, NAGAI DT. ; & www. Padasalai. Net

Questions and Answers

1.

The electrostatic force between two point charges kept at a distance d apart, in a medium ε_r = 6, is 0.3 N. The force between them at the same separation in vacuum is
- A.
  
  1.8 N
- B.
  
  0.5 N
- C.
  
  20 N
- D.
  
  2 N
2.

Elecric field intensity is 400 V m⁻¹ at a distance of 2 m from a point charge. It will be 100 V m⁻¹ at a distance?
- A.
  
  4 m
- B.
  
  4 cm
- C.
  
  1.5 m
- D.
  
  50 cm
3.

Two point charges +4q and +q are placed 30 cm apart. At what point on the line joining them the electric field is zero?
- A.
  
  20 cm from the charge 4q
- B.
  
  15 cm from the charge q
- C.
  
  7.5 cm from the charge q
- D.
  
  5 cm from the charge q
4.

A dipole is placed in a uniform electric field with its axis parallel to the field. It experiences
- A.
  
  Neither a net force nor a torque
- B.
  
  Only a torque
- C.
  
  Both a net force and torque
- D.
  
  Only a net force
5.

The work done in moving 500 μC charge between two points on equipotential surface is
- A.
  
  Zero
- B.
  
  Finite positive
- C.
  
  Finite negative
- D.
  
  Infinite
6.

Which of the following quantities is scalar?
- A.
  
  Electric potential
- B.
  
  Electric force
- C.
  
  Electric field
- D.
  
  Dipole moment
7.

The capacitance of a parallel plate capacitor increases from 5 μf to 60 μf when a dielectric is filled between the plates. The dielectric constant of the dielectric is
- A.
  
  12
- B.
  
  55
- C.
  
  65
- D.
  
  10
8.

A hollow metal ball carrying an electric charge produces no electric field at points
- A.
  
  Inside the sphere
- B.
  
  On its surface
- C.
  
  Outside the sphere
- D.
  
  At a distance more than twice
9.

A glass rod rubbed with silk acquires a charge of . The number of electrons it has gained or lost (1) (gained) (2) (lost) (3) (lost) (4) (lost)
- A.
  
  (2)
- B.
  
  (1)
- C.
  
  (4)
- D.
  
  (3)
10.

If a point lies at a distance x from the midpoint of the dipole, the electric potential at this point is proportional to (1) (2) (3) (4)
- A.
  
  (1)
- B.
  
  (2)
- C.
  
  (3)
- D.
  
  (4)
11.

Four charges +q, +q, −q and –q respectively are placed at the corners A, B, C and D of a square of side a. The electric potential at the center O of the square is (1) (2) (3) (4) zero
- A.
  
  (4)
- B.
  
  (3)
- C.
  
  (2)
- D.
  
  (1)
12.

Electric potential energy (U) of two point charges is (1) (2) (3) pE cos θ (4) pE sin θ
- A.
  
  (2)
- B.
  
  (3)
- C.
  
  (1)
- D.
  
  (4)
13.

The unit of permittivity is (1) C² N⁻¹ m⁻² (2) N m² C⁻² (3) H m⁻¹ (4) N C⁻² m⁻²
- A.
  
  (1)
- B.
  
  (2)
- C.
  
  (3)
- D.
  
  (4)
14.

The number of electric lines of force originating from a charge of 1 C is (1) (2) (3) (4)
- A.
  
  (1)
- B.
  
  (2)
- C.
  
  (3)
- D.
  
  (4)
15.

The electric field outside the plates of two oppositely charged plane sheets of charge density σ is (1) (2) (3) (4) zero
- A.
  
  (4)
- B.
  
  (3)
- C.
  
  (2)
- D.
  
  (1)