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MHT CET 2023 (13 May, Shift 1) · Splitting & Merging of Drops

Splitting & Merging of Drops question from MHT CET 2023 (13 May, Shift 1)

Q41MHT CET 2023 · 13 MAY · SHIFT 1Difficult

Splitting & Merging of Drops

A large number of water droplets each of radius 'rr' combine to form a large drop of Radius 'RR'. If the surface tension of water is 'TT' & mechanical equivalent of heat is 'JJ' then the rise in temperature due to this is

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Answer: (c)

  1. Energy released =3VT(1r−1R)= 3VT\left(\frac{1}{r} - \frac{1}{R}\right) (area change ×T\times T, with V=43πR3V = \frac{4}{3}\pi R^3).
  2. Heat =3VTJ(1r−1R)=msΔθ=VρsΔθ= \frac{3VT}{J}\left(\frac{1}{r} - \frac{1}{R}\right) = m s \Delta\theta = V \rho s \Delta\theta
  3. For water in CGS units ρ=1\rho = 1, s=1s = 1: Δθ=3TJ(1r−1R)\Delta\theta = \frac{3T}{J}\left(\frac{1}{r} - \frac{1}{R}\right)
  4. So the answer is (c).
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