18596. Degree of saturation or percentage humidity is

[A]. the mass of water vapour present in 1 m3 of dry air
[B]. the mass of water vapour present in 1 kg of dry air
[C]. the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
[D]. the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure
✅ The correct answer is option C.

18597. Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ρ = Density of fluid, cp = Specific heat at constant pressure, and μ = Coefficient of absolute viscosity)

[A].
[B].
[C].
[D].
✅ The correct answer is option C.