Question

Which physical quantity is measured in barn?

• A. \(\text{Radius of the nuclei} \)
• B. \(\text{Pressure in a liquid drop} \)
• C. \(\text{Scattering cross-section} \)
• D. \(\text{Rate of flow of liquid} \)

Hint:

The unit "barn" is widely used in nuclear and particle physics to describe cross-sections in scattering and nuclear interactions.

Answer 1

The Correct Option is C

Step 1: Understanding the unit "barn"
The barn (\( b \)) is a unit of area commonly used in nuclear physics to express the cross-sectional area of nuclear reactions. It is defined as: \[ 1 \text{ barn} = 10^{-28} \text{ m}^2 \] Step 2: Application in Scattering Cross-Section
- The scattering cross-section represents the effective target area that a nucleus presents to an incoming particle in a nuclear reaction.
- It is crucial in understanding interactions such as neutron scattering and nuclear fission.
- Since the barn is used specifically in nuclear and particle physics, the correct physical quantity measured in barn is scattering cross-section.
Final Answer: The correct option is Scattering cross-section (Option 3).