The excess pressure inside a soap bubble of diameter 1 mm is (surface tension =60 × 10-3 N / m )

Question

The excess pressure inside a soap bubble of diameter 1 mm is (surface tension =60 × 10-3 N / m ) (A) 240 N / m 2 (B) 0.48 N / m 2 (C) 480 N / m 2 (D) 0.24 N / m 2

Tardigrade Admin · Accepted Answer

Excess pressure p=(4 T/r) where T is surface tension and r the radius of drop. Given, r=(d/2)=(1/2) m m=(1/2) × 10-3 m, T=60 × 10-3 N / m ∴ P=(4 × 60 × 10-3/(1)2 × 10-3)=480 N / m 2

Q. The excess pressure inside a soap bubble of diameter $1 mm$ is
(surface tension $= 60 \times 1 0^{- 3} N / m$ )

$240 N / m^{2}$

$0.48 N / m^{2}$

$480 N / m^{2}$

$0.24 N / m^{2}$

Excess pressure $p = \frac{4 T}{r}$
where $T$ is surface tension and $r$ the radius of drop.
Given, $r = \frac{d}{2} = \frac{1}{2} mm = \frac{1}{2} \times 1 0^{- 3} m$ ,
$T = 60 \times 1 0^{- 3} N / m$
$∴ P = \frac{4 \times 60 \times 1 0 ^{- 3}}{\frac{1}{2} \times 1 0 ^{- 3}} = 480 N / m^{2}$

Q. The excess pressure inside a soap bubble of diameter 1mm is (surface tension =60×10−3N/m )

240N/m2

0.48N/m2

480N/m2

0.24N/m2