Question

Five styrofoam balls are suspended from insulating threads. Several experiments are performed on the balls and the following observations are made - (i) Ball A repels C and attracts B (ii) Ball D attracts B and has no effect on E (iii) A negatively charged rod attracts both A and E. An electrically neutral styrofoam ball gets attracted if placed nearby a charged body due to induced charge. What are the charges, if any, on each ball?

• A. A $\to$ + , B $\to$ - , C $\to$ + , D $\to$ 0 , E $\to$ +
• B. A $\to$ + , B $\to$ - , C $\to$ + , D $\to$ +, E $\to$ 0
• C. A $\to$ + , B $\to$ - , C $\to$ + , D $\to$ 0 , E $\to$ 0
• D. A $\to$ - , B $\to$ + , C $\to$ - , D $\to$ 0 , E $\to$ 0

Answer 1

Answer: (C)

A $\to$ + , B $\to$ - , C $\to$ + , D $\to$ 0 , E $\to$ 0

Answer 2

From (i) A and C both are charged, either positively or negatively. From (ii) Both D and E has no charge and from (iii), A is positively charged. Therefore from (i), B is negatively charged.