Question

A coaxial cylinder made of glass is immersed in liquid of surface tension ' S'. Radius of inner and outer surface of cylinder are R1 and R2 respectively. Height till which liquid will rise is (Density of liquid is p):

Options

• `(2"S")/("R"_2rho"g")`

• `(2"S")/("R"_1rho"g")`

• `"S"/(("R"_2-"R"_1)rho"g")`

• `(2"S")/(("R"_2-"R"_1)rho"g")`

Answer 1

`bb((2"S")/(("R"_2-"R"_1)rho"g"))`

Explanation:

Net upward force = 2π R₂S + 2pR₁S contact angle = 0°

∴ Capillary rise is given by

h = `(2pi"S"("R"_1+"R"_2))/(pi("R"_2^2-"R"_1^2)rho"g")`

= `(2"S")/(("R"_2-"R"_1)rho"g"))`