A soap bubble of radius R is blown. After heating the solution a second bubble of radius 2 R is blown. The work required to blow the second bubble in comparison to that required for the first bubble is

Options

A. Double
B. Slightly less than double
C. Slightly less than four times
D. Slightly more than four times

Answer

C

Explanation

`W_1 = 8pi R^2 T_1`
`W_(2) = 8pi (2R)^(2) T_(2) = 32 piR^2 T_2`
`W_1/W_2=T_1/(4T_2),W_2=4W_1T_2/T_1`
as temperature `uarr` surface tension `uarr`
`:. W_2 lt 4W_1`