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MHT CET 2023 (10 May, Shift 2) · Splitting & Merging of Drops

Splitting & Merging of Drops question from MHT CET 2023 (10 May, Shift 2)

Q42MHT CET 2023 · 10 MAY · SHIFT 2Difficult

Splitting & Merging of Drops

'nn' number of liquid drops each of radius 'rr' coalesce to form a single drop of radius 'RR'. The energy released in the process is converted into the kinetic energy of the big drop so formed. The speed of the big drop is

[T=[T = surface tension of liquid, ρ=\rho = density of liquid.]

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Answer: (d)

  1. Energy released =T ΔA=3VT(1r−1R)= T\,\Delta A = 3VT\left(\frac{1}{r} - \frac{1}{R}\right), where V=43πR3V = \frac{4}{3}\pi R^3.
  2. KE of big drop =12(ρV)v2= \frac{1}{2}(\rho V) v^2
  3. 12ρVv2=3VT(1r−1R)⇒v=6Tρ[1r−1R]\frac{1}{2}\rho V v^2 = 3VT\left(\frac{1}{r} - \frac{1}{R}\right) \Rightarrow v = \sqrt{\frac{6T}{\rho}\left[\frac{1}{r} - \frac{1}{R}\right]}
  4. So the answer is (d).
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