The correct option (A) 104(m/s)
Explanation:
Electric field = E = (v/d) = [(Potential difference)/(separation between plates)]
= [(300v)/(2 × 10–2)]
= 15 × 103v/m
also y = (1/2)at2
where a = (F/m) = (qE/m) ------- Force = mass × acceleration & time = [(distance)/(velocity)]
and t = (x/u)
∴ y = (1/2) (qE/m) (x/u)2
∴ u2 = (1/2) [(qEx2)/(my)]
= (1/2) × [{1.6 × 10–19 × 15 × 103 × (0.1)2}/(12 × 10–24 × 0.01)]
u2 = 108
u = 104(m/s)