What unit of work or energy is equivalent to 0.624 x 10^18 electron volts?

• A. Joules
• B. Ergs
• C. Calories
• D. Electronvolts

Answer: (B)

This question tests converting energy from electron volts to another energy unit using standard relationships. Start with 0.624 × 10^18 eV and use 1 eV = 1.602 × 10^-19 J, and 1 J = 10^7 ergs.

First convert to joules:

0.624 × 10^18 eV × 1.602 × 10^-19 J/eV ≈ 0.100 J.

Then convert joules to ergs:

0.100 J × 10^7 erg/J ≈ 1.0 × 10^6 erg.

So the energy is about 1 million ergs, making erg the best match among the options. (For perspective, this is about 0.1 J or roughly 0.0239 cal, but the discrete choice that fits the given units is erg.)