The surface area of a rectangular film of a liquid is extended from `10 cm xx" 6 cm to 12 m" xx 10 cm.` If the work done during this process is `6 xx 10^(-4)J` and surface tension of liquid is `n xx 10^(-2)" N/cm"`, find the value of n.

Explanation

`triangleA=` Increase of area
`=2(12 xx 10-10 xx 6)cm^(2)`
`=120cm^(2)=120 x 10^(-4) m^(2)`
Surface tension `=("Work done")/("Increase in area")`
`=(6 xx 10^(-4))/(120 xx 10^(-4))`