7.1 The Nature of Light Flashcards
electromagnetic radiation
consists of energy propagated by electric and magnetic fields that increase and decrease in intensity as they move through space
frequency (v)
the number of cycles it undergoes per second; unit = 1/second [s^-1; hertz (Hz)]
Wavelength (λ)
the distance between any point on a wave and the corresponding point on a wave and the corresponding point on the next crest (or trough) of the wave (the distance the wave travels during one cycle); units = meters, nanometers (10^-9m), picometers (10^-12m), angstroms (Å, 10^−10m)
speed
the distance it moves per unit time (meters per second), the product of its frequency (cycles per second) and wavelength (meters per cycle); units for speed of wave = (cycle/s) x (m/cycle) = m/s
speed of light (c)
3.00x10^8 m/s;
c = v · λ
Relation of frequency and wavelength
high frequency has a short wavelength; long wavelength has a short frequency:
v↑ λ↓ and v↓ λ↑
amplitude
the height of the crest (or depth of the trough)
related to the intensity of the radiation
regions of the electromagnetic spectrum by increasing wavelength (λ)
Gamma Ray
refraction
the speed of a light wave passing between media changes immediately
dispersion
white light separates (disperses) into its component colors when it passes through a prism or other refracting object
diffraction
when a wave strikes the edge of an object, it bends around it
interference
when waves of light pass through two adjacent slits, the nearby emerging circular waves interact
the quantum theory (equation and definition)
a hot, glowing object could emit (or absorb) only certain quantities of energy: E = nhv *n = positive integer *h = planck's constant *v = frequency
Planck’s constant (h) equation
units of J · s
h = 6.626 x 10^-34 J · s
photoelectric effect
when monochromatic light sufficient frequency shines on a metal plate, a current flows
