A metallic wire of diameter `d` is lying horizontally o the surface of water. The maximum length of wire so that is may not sink will be

Options

A. `r=sqrt((2T)/(pi dg))`
B. `r=sqrt((pi dg)/(2T))`
C. `r=sqrt((2T)/(pi dg))`
D. `r=sqrt((2dg)/(piT))`

Answer

C

Explanation

Upward force due to S.T
= Downwars force due to weight
` :. 2(TL) = mg = pir^(2) ` Ldg
` :. r^(2) =(2T)/(pidg) :. sqrt((2T)/(pidg))`