A cube with mass `m = 20 g` wettable by wter floats on the surface of water. Each face of the cube is `3 cm` long. If the distance `(cm)` between the lower face of the cube and the surface of the water in cotact with the cube is `4.6 lambda cm`, then find `lambda` ? [`S.T` of water `alpha = 30 dyn//cm`, assume contact angle to be `theta = 0^(@)`]

Answer

`2`

Explanation

`F_(e) =` buoyent force `F_(s) =` surface tension force
`rArr -(4a) xx alpha xx d + d xx g xx a^(2)h = mg`.
`rArr h = (mg + 4aalpha)/(dga^(2)) = 2.3 cm`