Question

Two charged spheres repel each other with force of 2*10^3n the charge on one sphere is twice of other calculate initial charges when they are moved 10 cm

Answer 1

Given in the question :- Refers to the attachment 

Force F = 2 × 10³ N.
Charge on one sphere = q 
Charge on other sphere = 2q
distance r = 10 cm = 0.1 m

Now , we know the formula. 

$F = k \frac{q_{1}q_{2}}{r^2}$ 
2 × 10 ³ = (9× 10⁹ × q²) / ( 0.1)²
q² = (10³ × 10⁻²)/ (9 × 10⁹)
q² = 10/ (9 × 10⁹)
q² = 1.11 × 10⁻⁹
q = √(1.11 × 10⁻⁹)
q = 3.3 × 10⁻⁵  C


Hope it Helps :-)