Step 1: Understanding the Concept
Average translational kinetic energy of a gas molecule is \(E_1 = \frac32 kT\), with Boltzmann constant \(k = R/N\) (N being the Avogadro number here). An electron accelerated through V volts gains \(E_2 = eV\).
Step 2: Equate
\[ \frac32\cdot\frac{R}{N}T = eV \Rightarrow T = \frac{2eVN}{3R} \]
Option (A) has the factor 2 in the denominator instead of the numerator, and (C) leaves out the 3/2.
Final Answer:
The temperature is \(\dfrac{2eVN}{3R}\), option (B).
\[ \boxed{\frac{2eVN}{3R}} \]