1. Two equal charges + q are placed at points A and B. A small charge –q0 at the midpoint C joining A and B. If –q0 is slightly displaced along a straight line perpendicular to AB and release it will:
(a) remain stationary in the displaced position
(b) come back to C
(c) continue to move away from C
(d) oscillate about C
2. 27 identical drops of mercury , charged to same potential of 10V are made to combine to form one large drop. The potential of the large drop will be:
(a) 45V
(b) 90 V
(c) 135 V
(d) 270 V
3. An infinite number of electric charges each equal to Q are placed on the x=axis at x = 1 , 2 , 4, 8,……….. metre. The potential at x = 0 will be :
(a) zero
(b) Q/6πε0
(c) Q/2πε0
(d) infinite
5. Charge Q is placed at the centre of a circle of radius R. charge q is at a distance r from Q. r < R. Charge q is moved alternately to two points one the circumference of the circle. The ration of the distance of these points from q is 1:2. The work done in first case W1 is related to the work done in the second case by :
(a) W1 > W2
(b) W1 = W2
(c) W1 < W2
(d) W1 = W2
6. A charge Q is placed at the centre of a cube. The electrical flux across a face of the square is :
(a) Q/4πε0
(b) Q/ε0
(c) Q/6ε0
(d) Q/4ε0
7. A parallel plate capacitor is charged by connecting is plates to he terminals of a battery. The battery remains connected and a glass plate in interposed between the plates of the capacitor, then:
(a) the charge on the plates will be reduced
(b) the p.d between the plates will be reduced
(c) the charge on the plates will increase
(d) the p.d. between the plates will increase
8. A parallel plate capacitor with plate area A and B separation d is filled with laminar strips of two dielectrics of permittivity’s ε1 and ε2 such that the volume occupied by each medium is the same. The capacitance of the capacitor is:
(a) 2 (ε1 + ε2) A/d
(b) 2 ε1 + ε2 A/d (ε1 + ε2)
(c) 2 (ε1 + ε2) A/d ε1 + ε2
(d) (ε1 + ε2) A/d .
9. Two capacitors C1 and C2 are connected in parallel and a total charge Q is given to the combination the ratio of the charge C1 to that C2 is :
(a) C1/C2
(b) C1 C2
(c) C2/C1
(d) 1/C1C2
10. Two insulated charged spheres of radii 0.2 m and 0.25 m respectively each carry the same charge + q. If connected by a thin copper wire and then separated :
(a) both spheres will have same charge + q
(b) charge on the smaller sphere will be more than that on the large one
(c) charge on the smaller sphere will be less than that on the larger one
(d) charge on each sphere will be +2q
Answer Keys:
1. (d) 2. (b) 3. (c) 4. (b) 5. (b) 6. (c) 7. (c) 8. (b) 9. (c) 10. (c)
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