Question

Nuclear sizes are expressed in the unit:

• A. Tesla
• B. Newton
• C. Angstrom
• D. Fermi

Hint:

Nuclear radius is around 10 to the power minus 15 metres, find which listed unit matches exactly this scale.

Answer 1

The Correct Option is D

Step 1: Note the scale of nuclear size.
The radius of an atomic nucleus is extremely small, of the order of \(10^{-15}\) m.
Step 2: Recall the matching unit.
A unit called the fermi (symbol fm) is defined such that 1 fermi equals \(10^{-15}\) m, chosen specifically to match the scale of nuclear dimensions, and named after physicist Enrico Fermi.
Step 3: Compare with the other listed units.
Tesla measures magnetic field strength, Newton measures force, and angstrom (\(10^{-10}\) m) measures atomic and molecular sizes, which are far larger than nuclear sizes.
Step 4: Draw the conclusion.
Since nuclear radii match the scale of \(10^{-15}\) m exactly, the fermi is the standard unit used to express nuclear size.
Final Answer: D) Fermi.