nucleon: proton/neutron inside nucleus
| Charge/C | Charge RTP | Mass/kg | Mass RTP | |
|---|---|---|---|---|
| proton | $+1.60\times10^{-19}$ | $1$ | $1.67\times10^{-27}$ | $1$ |
| neutron | $0$ | $0$ | $1.67\times10^{-27}$ | $1$ |
| electron | $-1.60\times10^{-19}$ | $-1$ | $9.11\times10^{-31}$ | $0.0005$ |
| ---------- | ----------------------- | ---------------------- | ---------------------- | ------------------------- |
RTB = relative to proton
Specific Charge of charged particle: $\frac{charge}{mass}$
$charge = 1.60\times10^{-19}$
$mass = 1.67\times10^{-27}$
$\frac{charge}{mass} = 9.58\times10^{7}Ckg^{-1}$
$charge = -1.60\times10^{-19}$
$mass = 9.11\times10^{-31}$
$\frac{charge}{mass} = -1.76\times10^{11}Ckg^{-1}$
$^{16}_{8}O$
$charge = 1.2\times10^{-18}$
$mass = 2.67\times10^{-26}$
$\frac{charge}{mass} = 4.49\times10^{7}Ckg^{-1}$
$[^{24}_{12}Mg]^{+2}$
$charge = 3.20\times10^{-19}$
$mass = 3.98\times10^{-26}$
$\frac{charge}{mass} = 8.04\times10^{6}Ckg^{-1}$
The Strong Nuclear Force holds together the nuclei in a stable isotope so it doesn't disintegrate.
The Strong Nuclear Force overcomes the electrostatic repulsion between the protons.
Info:
| Type | radio | microwave | infrared | visible | ultraviolet | X-rays | gamma rays |
|---|---|---|---|---|---|---|---|
| Wavelength range | >0.1m | 0.1m-1mm | 1mm-700nm | 700nm-400nm | 400nm-1nm | 10nm-0.001nm | <1nm |
When charged particle loses energy, it emits an electromagnetic wave.
Happens when:
Positron: antiparticle of electron
$hf_{min} = 2\times0.511$
$hf_{min} = 1.022MeV$
$hf_{min} = 1.64\times10^{-13}J$
$f_{min} = 2.47\times10^{20}J$
The weak nuclear force can change neutrons into protons and protons into neutrons.
In $\beta^-$ or $\beta^+$ decay:
Due to exchange of W bosons particles
Electron capture:
| Particle and symbol | proton charge | Antiparticle and symbol | antiparticle proton charge | Rest energy (MeV) | Interaction |
|---|---|---|---|---|---|
| proton p | +1 | antiproton $\bar{p}$ | -1 | 938 | strong, weak, electromagnetic |
| neutron n | 0 | antineutron $\bar{n}$ | 0 | 939 | strong, weak |
| electron $e^-$ | -1 | positron $e^+$ | +1 | 0.511 | weak, electromagnetic |
| neutrino $v$ | 0 | antineutrino $\bar{v}$ | 0 | 0 | weak |
| muon $\mu^-$ | -1 | antimuon $\mu^+$ | +1 | 106 | weak, electromagnetic |
| pions $\pi^+$, $\pi^0$, $\pi^-$ | +1, 0, -1 | $\pi^-$, $\pi^0$, $\pi^+$ respectively | -1, 0, +1 | 140, 135, 140 | strong, electromagnetic ($\pi^+$, $\pi^-$) |
| kaons $K^+$, $K^0$, $K^-$ | +1, 0, -1 | -1, 0, +1 | 494, 498, 494 | strong, electromagnetic ($K^+$, $K^-$) |
Both these groups are composed of smaller particles called quarks and antiquarks
1.Interaction between lepton and hadron
2.Muon decay
3.Electron and muon neutrinos
quarks and antiquarks in hadrons:
| Quarks | Antiquarks | |||||
|---|---|---|---|---|---|---|
| up(u) | down(u) | strange(s) | up($\bar{u}$) | down($\bar{d}$) | strange($\bar{s}$) | |
| charge(Q) | $+\frac{2}{3}$ | $-\frac{1}{3}$ | $-\frac{1}{3}$ | $-\frac{2}{3}$ | $+\frac{1}{3}$ | $+\frac{1}{3}$ |
| strangeness(S) | 0 | 0 | -1 | 0 | 0 | +1 |
| baryon number(B) | $+\frac{1}{3}$ | $+\frac{1}{3}$ | $+\frac{1}{3}$ | $-\frac{1}{3}$ | $-\frac{1}{3}$ | $-\frac{1}{3}$ |
$p + \bar{p} \to \pi^+ + \pi^-$ (observed)
$p + \bar{p} \to p + \pi^-$ (not observed)
if we split them into quarks/antiquarks
$uud + \bar{u}\bar{u}\bar{d} \to u\bar{d} + \bar{u}d$ (observed)
$uud + \bar{u}\bar{u}\bar{d} \to uud + \bar{u}d$ (not observed)
with $+\frac{1}{3}$ for quarks, and $-\frac{1}{3}$ for antiquarks
with the observed one:
with the non observed one:
wave theory of light cant explain: threshold frequency, why no delay.
wave theory states conduction electrons should gain energy no matter f.
or $hf = E_{Kmax} + \phi$ rearranged
This means that it can only take place if $hf > \phi$
$\therefore$ threshold frequency = $f_{min} = \frac{\phi}{h}$
mercury atom de-excites from 4.9eV to ground state.
calculate the wavelength of photon released.
energy of photon $hf = E_1 - E_2$
$hf = 4.9 - 0 = 4.9eV$
$= 4.9 \times 1.6\times10^{-19}J = 7.84\times10^{-19}J$
frequency $f = \frac{E_1 - E_2}{h}$
$f = \frac{7.84\times10^{-19}}{6.63\times10^{-34}} = 1.18\times10^{15}Hz$
$\lambda = \frac{c}{f}$
$\lambda = \frac{3.0\times10^8}{1.18\times10^{15}} = 2.54\times10^{-7}$
$= 254nm$
energy levels, relative to ionisation level formula:
$E = -\frac{13.6eV}{n^2}$
where n = 1 for ground state, n = 2 for next state etc
This formula gives the energy of the photon released:
$E = (\frac{1}{(n_2)^2}-\frac{1}{(n_1)^2})\times13.6eV$
where electron de-excites from energy level $n_1$ to $n_2$
Light has dual nature. It can behave as wave or particle according to circumstances.
de Brogile hypothesis suggest matter particles also have wave like nature
A beam of electrons can be diffracted