Question

The surface tension of soap solution is 25 × 10^-3 Nm^-1. The excess of pressure inside a soap bubble of diameter 1 cm is ______.

Options

• 10 Pa

• 20 Pa

• 5 Pa

• None of these

Answer 1

The surface tension of soap solution is 25 × 10^-3 Nm^-1. The excess of pressure inside a soap bubble of diameter 1 cm is 20 Pa.

Explanation:

Excess pressure ΔP = `(4"T")/"r"`

= `(4xx2xx25xx10^-3)/(1xx10^-2)`

= 20 N/m²

= 20 Pa    (as r = d/2)