10 Question-Answer on electric charges
1. Two point charges certain distance apart in air repel each other with a force F. A glass plate is introduced between the charges. The force becomes F’, where
(a) F’ < F
(b) F’ =F
(c) F’ > F
(d) Data is insufficient
Ans: ( a)
2. Force between two charges separated by a certain distance in air is F. if each charge were doubled and distance between them also doubled , force would be:
(a) F
(b) 2F
(c) 4F
(d) F/4
Ans: (a)
3. An uncharged insulted conductor A is brought near a charged insulted conductor B.
(a) The charge and potential of B, both remain constant
(b) Both change
(c) The charge remains constant, but potential of B decreases
(d) The charge remains constant, but potential of B increases
Ans: (c)
4. Two charges are placed a certain distance apart. A metallic sheet is placed between them. What will happen to the force between the charges?
(a) Increase
(b) Decrease
(c) Remains unchanged
(d) Either ‘a’ or ‘b’
Ans: ( c)
5. The distinction between conductors, insulators and semiconductors is largely concerned with
(a) Their ability to conduct current
(b) The type of crystal lattice
(c) Binding energy of their electrons
(d) Relative widths of their energy gaps
Ans: (d)
6. A cylindrical conductor is placed near another positively charged conductor. The net charge acquired by the cylindrical conductor will be:
(a) Positive only
(b) Negative only
(c) Zero
(d) Either positive or negative.
Ans: (c)
7. Two spheres A and B of exactly same mass are given equal positive and negative charges respectively. Their masses after charging
(a) Remain unaffected
(b) Mass of A > mass of B
(c) Mass of A <mass of B
(d) Nothing can be said
Ans: (c)
8. The distance between two point charges is increased by 10% . the force of intraction
(a) Increased by 10%
(b) decreased by 10%
(c) decreased by 17%
(d) decreased by21%
Ans: ( c)
9. What happens when some charge is placed on a soap bubble?
(a) Its radius decreases
(b) Its radius increases
(c) The bubble collapses
(d) None of above
Ans: (b)
10. A positively charged rod is brought near uncharged conductor. If the rod is then suddenly withdrawn, the charge left on the conductor will be:
(a) Positive
(b) Negative
(c) Zero
(d) Not sure
Ans: ( c)