Physics · Application of surface tension: drops, bubbles and capillary rise

At certain temperature radius of an air bubble is doubled when it comes to the t

At certain temperature radius of an air bubble is doubled when it comes to the top from bottom of a mercury column of height H if the pressure is:

  • A. 5.5
  • B. 10.64
  • C. 12.45
  • D. 15

Step-by-step solution

Using Boyle's law: P1V1 = P2V2. At bottom, P1 = Patm + ρgH; at top, P2 = Patm. Radius doubles so V2 = 8V1. Thus, Patm + ρgH = 8Patm → ρgH = 7Patm. With Patm = 76 cm Hg = 0.76 m Hg, H = 7 × 0.76 = 5.32 m. The closest option is 5.5.
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