Question

The speeds of 5 molecules of a gas (in arbitrary units) are as follows : 2, 3, 4, 5, 6. The root mean square speed for these molecules is

• A. 2.91
• B. 3.52
• C. 4.00
• D. 4.24

Answer 1

Answer: (D)

4.24

Answer 2

$v_{rms} = \sqrt{\frac{v_{1}^{2} + v_{2}^{2} + v_{3}^{2} + v_{4}^{2} + v_{5}^{2}}{5}} = \sqrt{\frac{2^{2} + 3^{2} + 4^{2} + 5^{2} + 6^{2}}{5}} = \sqrt{\frac{100}{5}} = \sqrt{20} = 4.24$