What is the unit of energy in atomic and nuclear physics ? Define it.
What is the unit of energy in atomic and nuclear physics ? Define it.
Electron volt $(\mathrm{eV})$ is the unit of energy in atomic and nuclear physics.
$1 \mathrm{eV}$ (electron volt): When $1$ electron is accelerated under potential difference of $1$ volt energy acquired by it is called electron volt.
$\therefore 1 \mathrm{eV}=1.602 \times 10^{-19} \mathrm{~J}$ and $1 \mathrm{~J}=6.242 \times 10^{18} \mathrm{eV}$
Table $11.1$ : Work function of some metals
| metal |
Work function $\phi_{0}(e \mathrm{~V})$ |
Metal |
Work function $\phi_{0}(e \mathrm{~V})$ |
| $\mathrm{Cs}$ | $2.14$ | $\mathrm{Al}$ | $4.28$ |
| $\mathrm{K}$ | $2.30$ | $\mathrm{Hg}$ | $4.49$ |
| $\mathrm{N} a$ | $2.75$ | $\mathrm{C} u$ | $4.65$ |
| $\mathrm{C} a$ | $3.20$ | $\mathrm{Ag}$ | $4.70$ |
| $\mathrm{Mo}$ | $4.17$ | $\mathrm{N} i$ | $5.15$ |
| $\mathrm{P} b$ | $4.25$ | $\mathrm{P} t$ | $5.65$ |
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