MCQ
Which of the following statement is true
  • Absolute zero degree temperature is not zero energy temperature
  • B
    Two different gases at the same temperature pressure have equal root mean square velocities
  • C
    The root mean square speed of the molecules of different ideal gases, maintained at the same temperature are the same
  • D
    Given sample of $1\, cc$ of hydrogen and $1\, cc$ of oxygen both at $NTP;$ oxygen sample has a large number of molecules

Answer

Correct option: A.
Absolute zero degree temperature is not zero energy temperature
a
$(A)$ $\rightarrow K \cdot E$ is given by $\left(K \cdot E=\frac{3}{2} \cdot K_B \cdot T\right)$. If. $T$ is zero, then $K E$ will be zero. But the Potential Energy still remains It may or maynot be zero. Thus, Absolulé zero temperature is not zero energy temp. option $A$ is correct.

$(B)$ $\rightarrow$ R.Ms. velocity $=\sqrt{\frac{3 R T}{M}}$, So it depends on Mass olso. So two different gases will have different R.M.S velocities. So option $B$ is incorrect.

$(C)$ $\rightarrow$ Similar as above option B. R.M.S depends on molar mass also. So. option $C$ is ircorrect.

$(D)$ $\rightarrow$ No. of molecules $=\frac{\text { mass }}{\text { molar mass }}$ So, no. of molecules is inversely paportional to molar mass. The molar mass of oxygen molecules are more, so No. of molecules of oxygen will be less. option. $D$ is incorrect.

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