Question 311: Thermodynamics & KTG

Question

The root mean square speed of smoke particles of mass $$5 	imes 10^{-17} \mathrm{~kg}$$ in their Brownian motion in air at NTP is approximately. [Given $$\mathrm{k}=1.38 	imes 10^{-23} \mathrm{JK}^{-1}$$]

Accepted Answer

At NTP, $T=298 \mathrm{~K}$
$$
\begin{aligned}
 v_{\mathrm{rms}} &=\sqrt{\frac{3 R T}{M}} \
&=\sqrt{\frac{3 k N_{A} 	imes 298}{5 	imes 10^{-17} 	imes N_{A}}}
\end{aligned}
$$
$\simeq 15 \mathrm{~mm} / \mathrm{s}$

Answer

$$60 \mathrm{~mm} \mathrm{~s}^{-1}$$

Answer

$$12 \mathrm{~mm} \mathrm{~s}^{-1}$$

Answer

$$15 \mathrm{~mm} \mathrm{~s}^{-1}$$

Answer

$$36 \mathrm{~mm} \mathrm{~s}^{-1}$$

Thermodynamics & KTG

The root mean square speed of smoke particles of mass $5 \times 10^{-17} \mathrm{~kg} in their Brownian motion in air at NTP is approximately. [Given \mathrm{k}=1.38 \times 10^{-23} \mathrm{JK}^{-1}$]

Choose the correct answer: