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Instantaneous rate of effusion is directly proportional to the instaneous gas pressure and

inversely proportional to the square root of molar mass.

Decrease in pressure of a cylinder per unit time is called rate of effusion of gas

Value of molar gas constant (R) = 623600 torr ${\text{CCK}}^{-1}mo{l}^{-1}$

Volume remaining constant, the pressure of a given mass of a gas increase or decreases by

$\frac{1}{273}$ of its pressure at 0°K perdegree change of temperature