Question

A charged metallic bob of mass m and charge Q is in equilibrium in presence of electric repulsion by Q(fixed) as shown. Find Q

Answer 1

Given that,

Mass of bob = m

Charge = Q

We need to calculate the value of Q

Using relation of electric force and gravitational force

$F=\dfrac{kQ}{r^2}$

$\dfrac{Gm}{r^2}=\dfrac{kQ}{r^2}}$

Where, m = mass of bob

Q = charge

$Q=\dfrac{r^2Gm}{kr^2}$

$Q=\dfrac{Gm}{k}$

Hence, The value of Q is $\dfrac{Gm}{k}$

Answer 2

Answer:

√(4π∈mg) L

Explanation:

Refer attachment

hope it helps