The root mean square speed of smoke particles of mass 5 × 10-17 in their Brownian motion in air at NTP is approximately. [Given k = 1.38 × 10-23 JK-1]
- 60 mm s-1
- 12 mm s-1
- 15 mm s-1
- 36 mm s-1
The Correct Option is C
Solution and Explanation
At NTP, T=298 K
⇒vrms=\(\sqrt\frac{3RT}{M}\)
\(=\sqrt{\frac{3kN_A×298}{5×10^{−17}×N_A}}\)
≃15 mm/s
So, the correct option is (C): 15 mm s-1
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Concepts Used:
Speed and Velocity
The rate at which an object covers a certain distance is commonly known as speed.
The rate at which an object changes position in a certain direction is called velocity.
Difference Between Speed and Velocity:
Read More: Difference Between Speed and Velocity