In the First Nuclear Reaction Observed, Physicists Saw an Alpha $( Z = 2 )$

question 103

Short Answer

In the first nuclear reaction observed, physicists saw an alpha particle $( Z = 2 )$ interact with a nitrogen nucleus in air $( Z = 7 )$ to produce a proton. The energy of the alpha particle was $55 \mathrm { MeV }$ , enough to enable the nuclei to touch in spite of the Coulomb repulsion. What distance (in fm) between the centers of the alpha particle and the nitrogen was reached? This determines a limit on the radius of the nitrogen nucleus. $\left( 1 \mathrm { eV } = 1.60 \times 10 ^ { - 19 } \mathrm {~J} , e = 1.60 \times 10 ^ { - 19 } \mathrm { C } , 1 / 4 \pi \varepsilon _ { 0 } = 8.99 \times 10 ^ { 9 } \mathrm {~N} \right.$ $\cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 }$ )

---

Definitions:

Vascular Tissue

Specialized tissue in plants that conducts water and nutrients throughout the plant body; includes xylem and phloem.

Xylem

A type of tissue in plants that transports water and some nutrients from the roots to the leaves.

Gymnosperms

Seed-producing plants that bear their seeds directly on the surfaces of cones, differing from flowering plants in their mode of reproduction.

Single Species

Refers to a specific, individual species as opposed to a group or community of multiple species.