Question

A metal sphere has a charge of 18.0 mC. What is the net charge after 6.0

1013 electrons have

been placed on it?

Answer 1

initial charge on metal sphere, Q = +18mC

a/c to question,

6 × 10¹³ electrons are placed on it.

we know, charge on each electron , e = -1.6 × 10^-19 C

so, charge on 6 × 10¹³ electrons , q = -6 × 10¹³ e = -6 × 10¹³ × 1.6 × 10^-19 C

= -9.6 × 10^-6 C

= -9.6 × 10^-3 mC

= -0.0096 mC

hence, final charge on metal sphere = +18mC - 0.0096mC

= 17.9904mC

hence, net charge on metal sphere after 6 × 10¹³ electrons have been placed on it is 17.9904mC