Properties Of Solids And Liquids Question 331
Question: Radius of a soap bubble is ‘r’, surface tension of soap solution is T. Then without increasing the temperature, how much energy will be needed to double its radius [CPMT 1991; Pb. PMT 2000; RPET 2001]
Options:
A) $ 4\pi r^{2}T $
B) $ 2\pi r^{2}T $
C) $ 12\pi r^{2}T $
D)$ 24\pi r^{2}T $
Show Answer
Answer:
Correct Answer: D
Solution:
$ W=8\pi T(R _{2}^{2}-R _{1}^{2})=8\pi T[{{(2r)}^{2}}-{{(r)}^{2}}]=24\pi r^{2}T $
