# In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully

In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully cooled rubidium atoms to the 20-200 nk temperature range. assuming (incorrectly) that the rubidium atoms behave like particles of a classical ideal gas, calculate the rms speed of a rubidium atom at a temperature of 85.0 nk. in the experiments one particular isotope of rubidium was used, rubidium-87. the molar mass of this isotope is 86.91 g/mol.

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1. kayleighanne3462 says:

0.00493 m/s

Explanation:

T = Temperature of the isotope = 85 nK

R = Gas constant = 8.341 J/mol K

M = Molar mass of isotope = 86.91 g/mol

Root Mean Square speed is given by

$v_r=\sqrt{\dfrac{3RT}{M}}\\\Rightarrow v_r=\sqrt{\dfrac{3\times 8.314\times 85\times 10^{-9}}{86.91\times 10^{-3}}}\\\Rightarrow v_r=0.00493\ m/s$

The Root Mean Square speed is 0.00493 m/s

2. Expert says:

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray

3. Expert says:

the right answer is 0.3 meters per second