Q104 / 150 · MHT CET 2025 (23 Apr Shift 1) · Physics
The excess pressure inside first soap bubble is three times that of a second soap bubble. The ratio of volumes of the first to second bubble
- A$1: 3$
- B$1: 9$
- Correct answerC$1: 27$
- D$27: 1$
Solution
Given that the excess pressure $P_1$ in the first soap bubble is three times that in the second, $P_2$, we have $P_1 = 3P_2$.
Using the formula for excess pressure in a soap bubble, $P = \frac{4T}{R}$, we substitute to obtain $\frac{4T}{R_1} = 3\left(\frac{4T}{R_2}\right)$.
Cancelling the common factor $4T$ yields $\frac{1}{R_1} = \frac{3}{R_2}$, which simplifies to $R_2 = 3R_1$.
The volume of a sphere is $V = \frac{4}{3}\pi R^3$, so the volume ratio is $\frac{V_1}{V_2} = \frac{R_1^3}{R_2^3} = \left(\frac{R_1}{R_2}\right)^3$.
Substituting $\frac{R_1}{R_2} = \frac{1}{3}$ gives $\frac{V_1}{V_2} = \left(\frac{1}{3}\right)^3 = \frac{1}{27}$.
Final Answer: $\boxed{\text{C}}$
Hence, the correct answer is option: 'C'.