Applying the condition of rotational equilibrium,

But

applying principle of moments
F (0.6)=100(0.8)
ÞF=133.3N

The two capacitor the circuit are in parallel order, hence

The work done in charging the equivalent capacitor is stored in the form of potential energy.
Hence,

applying the condition of rotational equilibrium

Since so electric field will point from plate 2 to plate 1.
The electron will experience an electric force, opposite to the direction of electric field, and hence move towards the plate 2.

Use work-energy theorem to find speed of electron when it strikes the plate 2.

Where is the required speed.

Net emf in the circuit here
volt
While the equivalent capacity

Charge on each capacitor

Potential difference across capacitor

Consider the charge distribution as shown. Considering the branch on upper side, we have



Here,
…(i)
…(ii)
From Eqs. (i) and (ii), we get


Similarly for the lower side branch
…(iii)
...(iv)
From Eqs. (iii) and (iv)

(say)
This charge will remain constant after switch is shifted from position 1 to position 2.


Energy dissipated80% of the initial stored energy .