UPSEE Solved Model Paper 7

The root mean square speed of gaseous molecules is given as :
urms = √

3RT

M

... (i)
where, R = Gas constant
T = Temperature of the gas
M = Molar mass of the gas
Average kinetic energy for n moles of a gas is given by
E =

3

2

nRT
Kinetic energy for 1 mole. i.e. molar kinetic energy is given by
E =

3

2

RT
or
RT =

2

3

E ... (ii)
Substituting equation (ii) in equation (i), we get
The root mean square speed is given by
urms = √

3× 2 3 E

M

urms = √

2E

M

Hence, option 'C' is correct