Answer:
The total charge on the rod is 41.18 nC
Step-by-step explanation:
Given;
length of glass rod, L = 10 cm = 0.1 m
radius of the rod, r = 4 cm = 0.04 m
Force of repulsion = 940 μN = 940 × 10⁻⁶ N
Charge on the bead = 6.5 nC = 6.5 × 10⁻⁹ C
Charge on the rod, Q = ?
From coulomb's law;
![F = (K[q_1][q_2])/(R^2)](https://img.qammunity.org/2021/formulas/physics/college/aebweh9jo0mgzi1u8jymrpcd4b5n0kqiql.png)
Where;
F is the force of repulsion in N
q₁ and q₂ are the charges on the bead and rod
R is the resultant distance between the two charges;

K is coulomb's constant = 8.99 x 10⁹ Nm²/C²

Therefore, the total charge on the rod is 41.18 nC