The Dual Nature of Light: Waves and Particles
Light: A Wave and a Particle
The Particle Nature of Light
Energy of light is contained in small packets called photons. This explains how light can travel through the vacuum of space and the phenomenon known as the Photoelectric Effect.
The Photoelectric Effect describes how light shining on a metal plate can give electrons enough energy to escape. Bright light has more energy than dim light, but interestingly, dim blue light can dislodge electrons while bright red light cannot.
- Low-frequency light
Essential Physics Equations and Formulas
Physics Equations & Formulas
Physics is filled with equations and formulas that deal with angular motion, Carnot engines, fluids, forces, moments of inertia, linear motion, simple harmonic motion, thermodynamics, and work & energy.
Here’s a list of some important physics formulas and equations to keep on hand — arranged by topic — so you don’t have to go searching to find them.
Angular Motion
Equations of angular motion are relevant wherever you have rotational motions around an axis. When
Read MoreNASA Explorer Program Missions
Name(s)
Launch Date
Mission
S 45A
May 25, 1961
Ionosphere research, failed to achieve orbit
EPE-A (S 3, Energetic Particle Explorer-A)
August 16, 1961
Energetic particle research
S 55A
August 25, 1961
Micrometeoroid research
EPE-B (Energetic Particle Explorer-B)
October 2, 1962
Energetic particle research
EPE-C (Energetic Particle Explorer-C)
October 27, 1962
Energetic particle research
S 55B
December 16, 1962
Micrometeoroid research
AE-A (Atmosphere Explorer-A)
April 3, 1963
Atmospheric research
IMP-A (IMP 1, Interplanetary
The Hartree-Fock Method for Approximating Wave Functions in Quantum Chemistry
The Hartree-Fock Method
For hydrogen, the exact wave function is known. For lithium and helium, very accurate wave functions have been calculated by including interelectronic distance in the variation function. For atoms of higher atomic number, the best approach to finding a good wave function lies in first calculating an approximate wave function using the Hartree-Fock procedure, which we shall outline in this section. The Hartree-Fock method is the basis for the use of atomic and molecular orbitals
Read MoreUnderstanding the Ellipse: Equations, Characteristics, and Examples
Ellipse as a Geometric Locus
The ellipse is defined as the geometrical locus formed by the set of all points in the plane, where the sum of the distances from two fixed points, known as the foci (plural of focus) of the ellipse, is a constant.
Characteristics and Elements of the Ellipse
V and V’ are the vertices of the ellipse and are also known as the endpoints of the major axis.
F and F’ are the foci of the ellipse.
B and B’ are the endpoints of the minor axis.
Segment 
is known as the major axis
Understanding Hyperbolas: Equations, Characteristics, and Examples
Hyperbola as a Geometric Locus
The hyperbola is defined as the geometric locus of all points in a plane where the difference of distances from two fixed points (called foci) is constant.
The equation of a hyperbola is similar to that of an ellipse, but instead of the sum of distances, it involves the difference of distances.
Ordinary Form of the Hyperbola Equation
Hyperbola with Horizontal Focal Axis and Center at the Origin (0, 0)
The equation for this hyperbola is: x2/a2 – y2/b2 = 1
Characteristics:
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