A) \[\text{6 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{-2}}}\text{J}\]
B) \[\text{6 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{-4}}}\text{J}\]
C) \[\text{3 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{-2}}}\text{J}\]
D) \[\text{3 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{-4}}}\text{J}\]
Correct Answer: B
Solution :
Key Idea: Surface tension T can be defined as the work done informing the soap film of unit surface area. Surface tension of a soap film is written as \[\text{T}\,\text{=}\,\frac{\text{work}\,\text{done}}{\text{area}}\] or \[\text{work}\,\text{done}\,\text{=}\,\text{T}\,\text{ }\!\!\times\!\!\text{ }\,\,\text{area}\] Here, \[=2\times 10\times 10\,c{{m}^{2}}\,=2\times {{10}^{-2}}\,{{m}^{2}},\] \[T=3\times {{10}^{-2}}N/m\] Hence, work done \[=3\times {{10}^{-2}}\,\times 2\times {{10}^{-2}}\] \[=6\times {{10}^{-4}}J\]
You need to login to perform this action.
You will be redirected in
3 sec
