Question

Root mean square speed of the molecules of ideal gas is $v$. If pressure is increased two times at constant temperature, then the rms speed will become

• A. $\frac {v}{2}$
• B. v
• C. 2v
• D. 4v

Answer 1

Answer: (B)

v

Answer 2

RMS speed of gas molecules does not depends on the pressure of gas (if temperature remains constant) because $p \propto \rho .$ If pressure is increased $n$ times density will also increase by $n$ time but $V_{ rms }$ remains constant.