# Electric Field and Potential : JEE Level Objective Questions (Set 02)

This page contains an updated set of objective questions (second part) on the chapter 'Electric Field and Potential', a major portion of electrostatics. Before going to attempt these problems, we recommend you to first solve Electric Field and Potential : JEE Level Objective Questions (Set 01)All  the questions provided below strictly follow the current syllabus of JEE Mains & Advanced. The carefully selected problems are arranged in a proper order according to the correct flow of topics in the syllabus.

### Single Option Correct Type Questions

Out of the four different choices following each question, only one is the correct (or the most correct) which you have to mark.

1. Two neutrons are kept at some distance from each other. They will
A) attract each other
B) repel each other
C) neither attract nor repel
D) cannot say

2. A point charge 'Q' is to be divided in two parts 'q' and 'Q-q'. To have the maximum electrostatic repulsion between the two parts (when they are placed at certain distance from each other), 'Q' and 'q' must hold the relation:
A) q = Q/2
B) q = Q/3
C) q = 3Q/2
D) q = Q/4

3. Two point charges repel each other with a force of 100 N. If one of the charges is increased by 10% and the other is decreased by 10%, the new electrostatic force of repulsion at the same separation would be
A) 100 N
B) 121 N
C) 99 N
D) none of these

4. Strength of electric field near a straight wire carrying a steady current is
A) directly proportional to the distance from the wire
B) proportional to inverse square of the distance from the wire
C) inversely proportional to the distance from the wire
D) zero

5. What is the maximum charge a metallic ball of 2 mm diameter can hold? Given, dielectric strength of air = 3 × 10⁶ V/m.
A) 3 nC
B) 1/3 nC
C) 2 nC
D) 1/2 nC

6. An electron is having some initial velocity in a direction different from that of a uniform electric field. The trajectory of electron would be
A) a straight line
B) a circle
C) an ellipse
D) a parabola

7. A point charge q₁ is moved along a circle of radius R in the electric field of another point charge q₂ at the centre of the circle. Work done by the electric field on the charge q₁ in half revolution is
A) zero
B) positive
C) negative
D) None of these

8. An electron is set free from rest in a region of space where nonzero electric field exists. Identify the correct statement:
A) The electron will start moving towards a region of higher potential
B) The electron will start moving towards a region of lower potential
C) The electron will start moving along a line of constant potential
D) The electron will not accelerate.

9. A hollow metallic sphere of diameter 10 cm is charged such that the electric potential on its surface is 10 V. The electric potential at the centre of the sphere is
A) 0 V
B) 10 V
C) same as at a point 5 cm away from the surface
D) same as at a point 20 cm away from the surface

10. Three point charges -q, -q and 2q are kept fixed at the vertices of an equilateral triangle. At the centroid of the triangle,
A) field is zero but the potential is nonzero
B) field is nonzero but the potential is zero
C) both field and potential are zero
D) both field and potential are nonzero

11. At a point inside a hollow charged spherical conductor, the electric potential is
A) constant
B) proportional to the distance from the centre
C) inversely proportional to the distance from the centre
D) inversely proportional to the square of the distance from the centre

12. Two identical rings A and B of diameter 0.2 m are mounted coaxially at a distance 0.5 m apart. The charges on the two rings are 2μC and 4μC respectively. What would be the work done in transferring a charge of 5μC from the centre of A to that of B?
A) 1.28 J
B) 0.72 J
C) 0.144 J
D) 2.24 J

13. A conducting charged sphere has surface density of charge σ. The electric field strength on its surface is E. Keeping σ unchanged, if the radius of the sphere is doubled, what will be the electric field strength on the new sphere?
A) E/2
B) E/4
C) 2E
D) E

14. In the previous problem, if V is the potential of the first sphere, then potential of the second spere will be
A) 2V
B) V/2
C) V/4
D) V

15. Which of the following quantities is discontinuous across a charged conducting surface?
A) Electric Potential
B) Electric Intensity
C) Both electric potential and intensity
D) None of the above

16. Two charged particles have charges 1 μC and -1 μC and mass 50 g each are held at rest at a separation of 2 m. Now the charges are set free. The speed of the particles when their separation is 1 m is
A) 1/5 m/s
B) 3/5 m/s
C) 3/10 m/s
D) 2/7 m/s

17. When two charges are moved away from each other, the electrostatic potential energy of the charges
A) increases
B) decreases
C) remains the same
D) may increase or decrease

18. The potential decreases uniformly from 120 V to 80 V as one moves along x-axis from x = -1 cm to x = +1 cm. The electric field intensity at the origin
A) must be equal to 20 V/cm
B) must be equal to 20 V/m
C) may be greater than 20V/cm
D) may be less than 20 V/cm

19. The field intensity in a certain region is given by E = k/x³. The potential at a point P(x,y,z), assuming the potential at infinity as zero, is
A) zero
B) k/2x²
C) 3k/x⁴
D) k/x²

20. A solid metallic sphere of diameter 20 cm is enclosed by a thin metallic shell of diameter 40 cm. A charge of 20 μC is provided to the inner sphere. What will be the heat generated in the process when the inner sphere is connected to the outer shell by a conducting wire?
A) 12 J
B) 9 J
C) 24 J
D) zero

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