Question

If more air is pushed in a soap bubble, the pressure in it

(a) decreases

(b) increases

(c) remains same

(d) becomes zero.

Answer 1

(a) decreases

Explanation: 

The excess pressure (w.r.t. atmospheric pressure) inside a soap bubble is given as  P'-P = 4S/R, {where P'-pressure inside the bubble, P- atmospheric pressure} 

It is clear that the excess pressure inside is inversely proportional to the radius. As more air is pushed in a soap bubble its radius increases hence the excess pressure inside decreases.