V rms (in m/s) for helium atoms at 4.85 k, less than one degree above helium's liquefaction temperature is calculated as 173.84 m/s.
Speed of the molecules in a gas is directly proportional to the temperature and inversely proportional to molar mass of the gas. We can also say that, as the temperature of a sample of gas is increased, molecules speed up then the root mean square molecular speed also increases.
As we know that, V rms = √3 KT/M he
Given T= 4.85 K, K= 1.38 *10^-23 and M he is 6.644 *10^-27.
=√ 3 * 1.38 *10^-23 * 4.85 / 6.644 *10^-27
V rms for helium atoms = 173.84 m/s
To know more about molecular speeds, refer
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