Question

Two small spheres 18 cm apart have
equal negative charges and repel each
other with the force of 6x10^-8 N. Find the
total charge on both spheres.
[Ans: q = 2.93x10^-7C]​

Answer 1

Answer:

Explanation:

Given Two small spheres 18 cm apart have

equal negative charges and repel each

other with the force of 6x10^-8 N. Find the

total charge on both spheres.

Given spheres apart will be r = 18 cm = 0.18  

So force repel each other F = 6 x 10^-8 N

We know that

Force = K q Q / r^2

Spheres have equal negative charges, so q = Q

Now force = kq^2 / r^2

    6 x 10^-8 = 9 x 10^9 x q^2 / 0.18^2

 9 x 10^9 q^2 = 6 x 0.18^2 x 10^-8

            So q^2 = 0.1944 x 10 ^-17 / 9  

      Now q^2 = 0.0216 x 10^-17

       Or q^2 = 0.216 x 10^-18

     Or q = 0.46 x 10^-9  

So q = 0.46 n C

Therefore charge on each sphere will be – 0.46 n C