Question

What is the force between two small charged spheres having charges of 2 × 10⁻⁷ C and 3 × 10⁻⁷ C placed 30 cm apart in air?

Answer 1

Given: q₁ = 2 × 10⁻⁷ C

q₂ = 3 × 10⁻⁷ C 
r = 30 cm = 0.3 m

To find: F = ?

Formula: F = `1/(4piε_0) * (q_1q_2)/r^2`

= `9 xx 10^9 xx (2 xx 10^-7 xx 3 xx 10^-7)/(0.3)^2`

= `(6 xx 10^-14 xx 9 xx 10^9)/0.09`

= `(54 xx 10^-5)/0.09`

= 600 × 10⁻⁵ 

= 6 × 10⁻³ N (repulsive in nature, as the two charges are like charges.)