Question

The nuclear radius of hydrogen atom will be ______.

• A. 1.5 fm
• B. 1.2 fm
• C. 2.3 fm
• D. 3.2 fm

Hint:

"fm" stands for \textbf{femtometer} (also called a Fermi), which is $10^{-15}$ meters. It is the standard unit for measuring nuclear sizes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The radius of a nucleus ($R$) depends on its mass number ($A$) according to the empirical formula $R = R_0 A^{1/3}$.
Step 2: Detailed Explanation:
For a Hydrogen atom, the nucleus is a single proton, so $A = 1$. The constant $R_0$ is approximately $1.2 \times 10^{-15}\text{ m}$ (or $1.2\text{ fm}$). $$R = 1.2 \times (1)^{1/3} = 1.2\text{ fm}$$
Step 3: Final Answer:
The nuclear radius is 1.2 fm.