46. Surface tension may be defined as
(a) The work done per unit area in increasing the surface area of a liquid under isothermal condition
(b) The work done per unit area in increasing the surface area of a liquid under adiabatic condition
(c) The work done per unit area in increasing the surface area of a liquid under both isothermal and adiabatic conditions
(d) Free surface energy per unit volume
Ans. a
(10)