Question:

The value closest to the thermal velocity of a Helium atom at room temperature (300K) in m/s is: [kB=1.4×10⁻²³J/K; mHe=7×10⁻²⁷kg]

1.3×10³

1.3×10⁵

1.3×10⁴

1.3×10²

Vp=√(3KT/m)
Vp=√(3 × 1.38 × 10⁻²³ × 300 / 7 × 10⁻²⁷)
On solving we will get
1.3 × 10³
Option D is correct answer