Q: When a big drop of water is formed from n small drops of water, the energy loss is 3 E , where E is the energy of the bigger drop. If R is the radius of the bigger drop and r is the radius of the smaller drop, then number of smaller drops (n) is
Sol: The energy of n small drops – the energy of the bigger drop = Energy loss by bigger drop
n × 4 π r2 × T – 4 π R2 × T = 3 × 4 π R2 × T
n × 4 π r2 = 12 π R2 + 4 π R2
⇒ n = 4 R2/r2