Two identical conductiing balls A and B have positive charges `q_(12) and q_(2)` respectively. But `q_(1) ne q_(2)`. The balls are brought together so that they touchj each each other and then kept in their original positions .The force between them is

Options

A. less than that before the balls touched
B. greater than that before the balls touched
C. Same as that before the balls touched
D. zero

Answer

b

Explanation

According to coulomb's law, the force of repusion between them is given by `F=(q_(1)q_(2))/(4piepsilon_(0)R^(2))`

When the charged speres A and B are borought in contact each sphere will attain equal charge q'
`q=(q_(1)+q_(2))/(2)`
Now ,the force of repulsion between them at the same distance r is
`F=(qxxq)/(4piepsilon_(0)r^(2))=(1)/(4piepsilon_(0))(q_(1)+q_(2))/(2)(q_(1)+q_(2))/(2)/(r^(2))=(q_(1)+q_(2))/((2)^(2))/(4piepsilon_(0)r^(2))`
As`(q_(1)+q_(2))/(2)^(2)gtq_(1)q_(2)rArrF'gtF`