MCQ
Pressure inside a soap bubble is greater than the pressure outside by an amount :

(given : $\mathrm{R}=$ Radius of bubble, $\mathrm{S}=$ Surface tension of bubble)

  • $\frac{4 S}{R}$
  • B
    $\frac{4 R}{S}$
  • C
    $\frac{S}{R}$
  • D
    $\frac{2 S}{R}$

Answer

Correct option: A.
$\frac{4 S}{R}$
a
There are two liquid-air surfaces in bubble so

$\Delta \mathrm{P}=2\left(\frac{2 \mathrm{~S}}{\mathrm{R}}\right)=\frac{4 \mathrm{~S}}{\mathrm{R}}$

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