1. A parallel plate condenser has a capacity of 10 μf. The distance between the plates in doubled without altering any other thing, the capacity (in μF) is now:
(a) 0.2
(b) 0.5
(c) 5
(d) 20
2. Three identical capacitors of capacity C, each are connected in series and this combination is connected in parallel with an identical condenser. The equivalent capacity of the whole combination is :
(a) 3C/4
(b) 4C/3
(c) 2C
(d) 3C
3. Three condensers of capacity C each, are connected as shows below in the figure :
The capacity of the combination between the points A and B is :
(a) 3C
(b) 3C/2
(c) 2C/3
(d) C/3
4. In a region where electric field is zero, the potential at a point.
(a) is zero every where
(b) is constant every where but not necessarily zero
(c) cannot be defined
(d) depends on the position of the point
5. The false statement for a dielectric medium is:
(a) If charge can be easily induced in the medium the dielectric constant is large
(b) The electric field within the medium in reduced due to induced charged on the surface
(c) The dielectric constant of the medium is small if it is metallic
(d) If it is vacuum, the value of dielectric constant is one
6. Two small charged balls are suspended from a common point of suspension by threads of equal length and negligible mass. Upon repulsion the threads make equal angles with the vertical. We may conclude that:
(a) masses of the balls are equal
(b) charges on the balls are equal
(c) both charges and the masses are equal
(d) neither the charges nor the masses are equal
7. Charges q1 and q2 are stationed at the centers of two identical cubes of side a meters an build up of a material of dielectric constant 4. If the centers of the cubes are held 2a apart with faces parallel each other the force of attraction repulsion between the charges is F. If the charges were instead held at a distance 2a apart in vacuum air the force of attraction repulsion between q1 and q2 is :
(a) 4F/9
(b) F/4
(c) 4F
(d) 9F/4
8. A conducting sphere A carries a charge + q. It is placed inside another conducting spherical shell B carrying charge Q. If A and B are connected by a wire:
(a) charge will flow from A to B
(b) Charge will flow from B to A
(c) charge will flow depending on the magnitude and sign of Q
(d) there will be no flow of charge
9. If the plates of charged parallel plate capacitor are brought closer together using insulated handles to move them.
(a) the charge on the plates increases
(b) the p.d across plates increase
(c) the p.d across plates decrease
(d) the p.d. across plates remains the same
10. Two point charges of + 10nC each are placed 1m apart in air. Then at the middle point of the line joining them:
(a) the field E = 0 and potential V=O[]
(b) E = 0 and V = 360 volts
(c) E = 720 N/C and V=0
(d) E=0 and V = –360 volts
Answer Keys:
1. (c) 2. (b) 3. (c) 4. (b) 5. (c) 6. (a) 7. (d) 8. (a) 9. (c) 10. (b)
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