9TH GRADE · LIGHT PHENOMENA
Interference, diffraction and spectra
Wave properties, dispersion, color and types of spectra.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
interference
Stable intensity redistribution upon superposition of matched light waves.
At some points the waves strengthen each other, at others they weaken each other, forming an alternation of maxima and minima.
diffraction
Deviation of waves from straight-line propagation near obstacles and holes, noticeable at comparable sizes.
A diffraction grating separates light into wavelengths and is used to observe spectra.
Dispersion and spectrum
Dispersion occurs due to the dependence of the refractive index on wavelength and separates white light into colors.
Continuous, line emission spectra and absorption spectra help determine the composition of a substance.
Physical quantities
Light wavelength
Spatial period of an electromagnetic wave of light.
Unit: meter ·
Lesson formulas
Relationship between frequency and length of light
The speed of light in a vacuum is equal to the product of wavelength and frequency.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.