Photo Effect, Photoelectric Effect

  1. Ph.- outer electron emission substance under the influence of electromagnetic radiation. Observed in gases, liquids and solids. External Ph. described by Einstein $$h \nu=A+\dfrac{m v_{\max }^{2}}{2}$$ where $h \nu$ — energy photon $A$ — work out and $\dfrac{m v_{\max }^{2}}{2}$ — the maximum kinetic energy of the electron, $h$ — Planck’s constant. Value $\nu_{0}=\dfrac{A}{h}$ called red border Ph.

Phosphorus (P)

— a chemical element, atomic number $15$, atomic mass $30.97376$. There alotropichnyh in three versions:

  1. White Ph.- crystals of white or yellow color, density $1830\ \mathrm{kg} / \mathrm{m}^{3}$, melting point $44\ ^{\circ} \! {\mathrm{C}}$.
  2. Red Ph. amorphous powder, density $2300\ \mathrm{kg} / \mathrm{m}^{3}$, melting point $590\ ^{\circ} \! {\mathrm{C}}$.
  3. Black in appearance Ph. similar to graphite, the density of $2700\ \mathrm{kg} / \mathrm{m}^{3}$.


— quantum field lattice vibrations. Ph. — quasiparticles with energy $\varepsilon=h \nu$ and momentum $\vec{p}=h \vec{k}$, where $\nu$ — the frequency, $\vec{k}$ — wave vector of the elastic waves propagating in the crystal, $h=\dfrac{h}{2 \pi}$, $h$ — Planck’s constant. Ph. the concept introduced by analogy with the quantum of the electromagnetic field — photons.

Focal Length of Thin Lenses

— the value $$ f=\frac{1}{(n-1)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)} $$ where $n$ — the refractive index of the lens material regarding environmental, $R_{1}$ and $R_{2}$ — radii of curvature of the front and rear (with respect to the subject) surfaces of the lens taken given the fact that convex (relative to the object) surface $R>0$, and for concave $R<0$. F. l. expressed in meters (m).


— random deviation of physical quantities on their averages. F. due to discrete (atomic) structure of matter, quantum nature of radiation and thermal motion of particles. Measure F. is the dispersion.

Finite Movement

— bound, that is limited in space, the motion of microparticles. F. m. Is the motion of a particle in the potential pit (eg., an electron in an atom, the nucleons in the nucleus, and others.). When F. m. Particle has a discrete spectrum of energy (com. Infinitive movement).