Question

Physics help please!

The figure shows two uncharged metal balls, X and Y, supported on insulating stands. A third ball, Z, carrying a negative charge, is brought near the first two. A conducting wire is then run between X and Y. The wire is then removed, and ball Z is finally removed. When this is all done it is found that:

Options: (choose the correct one)

a) ball X is — and ball Y is +

b) balls X and Y are both negatively charged

c) balls X and Y are both positively charged

d) balls X and Y are still uncharged

e) ball X is + and ball Y is —

Answer 1

The third ball Z induces a positive charge on the part of the Y ball closest to it and a negative charge on the Y ball away from it.

Similarly by the process of induction a positive charge is induced on the part of the X ball closest to the Y ball and a negative charge away from it. When a conducting wire is run between X and Y the excess negative charges on the Y ball neutralize the excess positive charges on the X ball so that the X ball becomes negatively charged while the Y ball becomes positively charged.

The correct option is a).