Question

One barn is equal to

• A. ${10}^{-30}{m}^2$
• B. ${10}^{28}{m}^2$
• C. ${10}^{-28}{m}^2$
• D. ${10}^{30}{m}^2$

Answer 1

Answer: (C)

A barn (symbol b ) is a unit of area. Originally used in nuclear physics for expressing the cross sectional area of nuclei and nuclear reactions, today it is used in all fields of high energy physics to express the cross sections of any scattering process and is best understood as a measure of the probability of interaction between small particles. A barn is defined as ${10}^{-28}{m}^2\left(100f{m}^2\right)$ and is approximately the cross sectional area of a nucleus.