A charge Q is transfered from an initially uncharged plastic ball to an identical ball 12 cm away. The force of attraction is then 17 mN. How many electrons were transfered from one ball to the other

The ball from which electrons are transferred will acquire Q charge and the ball receiving electrons will acquire - Q charge. force of attraction between them

= k Q² / d²

9 x 10⁹ x Q² /.12² = 17 X 10⁻³

Q² =.0272 X 10⁻¹²

Q =.1650 X 10⁻⁶ C

No of electrons =.1650 x 10⁻⁶ / 1.6 x 10⁻¹⁹

=.103125 x 10¹³

1.03125 x 10¹²