Question

Two small plastic spheres are given positive electric charges. When they are 15 cm apart the repulsive force between them has magnitude 0.22 N. What is the charge on each sphere?
a) If the two charges are equal?
b) If one sphere has four times the charge of the other?

Answer 1

Answer:

F = k q1 q2 / r^2

where k is 9 × 10 ^9

here q1 and q2 are same.

lets assume q so q ^2 = F R^2 / K

0.22 . .15 . .15/ 9 × 10 ^9

= 25 × 22 × 10 ^ -3

.55 C

Answer 2

When they are 15.0 cm apart, the repulsive force between them has magnitude 0.22 N.

distance=15cm or 0.15m Force=0.22N K=9x10^9 kgm^2/c^2 ( this is a constant value of K)

a. use the formula

use F = kQq / d²

a) 0.220 N = 8.99e9N·m²/C² * Q² / (0.15m)²

Q = 7.42e-7 C = 742 nC is the charge of each sphere .

as for b. use the same fromula

b) 0.220 N = 8.99e9N·m²/C² * 4Q * Q / (0.15m)²

Q = 3.71e-7 C

4Q = 1.48e-6 C = 1.48 µC

hope its helpful