Question

A thin liquid film formed between a `U-`shaped wire and a light slider supports a weight of `1.5 xx 10^(-2)N`(see figure). The length of the slider is `30 cm` and its weight neligible. The surfaces tension of the liquid film is :

A. `0.0125 Nm^(-1)`
B. `0.1 Nm^(-1)`
C. `0.05 Nm^(-1)`
D. `0.025 Nm^(-1)`

Answer 1

Correct Answer - D
`2TL = mg`
`T = (mg)/(2L) = (1.5 xx 10^(-2))/(2 xx 30 xx 10^(-2)) = (1.5)/(600) = 0.025 N//m`