Physics: Chapter 19

Issac Newton believed that light was composed of fast moving, unimaginable tiny particles which he called...

corpuscles

all wavelengths interfere constructively in the central light bright band, so that band is....

white

instead of the equally spaced bright bands produced by two slits, the pattern of a single slit has a...

wide, bright central band with dimmer bands on wither side

note:because light has much smaller wavelengths than sound the diffraction is much less obvious

woah man.

wavelengths of visible light can be so tiny that they could produce such....

small diffraction effects

Rayleigh criterion

"If the central band of one star falls on the first dark band of the second, the stars will be just resolved. That is, a viewer will be able to tell that there are two stars and not just one" -specifies the minimum separation between two light sources that may be resolved into distinct objects-

coherent waves

- Light waves that move together as they travel away from their source - two monochromatic light waves wavelengths maintain a constant phase relationship.

what does diffraction limit?

-resolving power of microscopes/telescopes -and limits the ability of a lens to distinguish two closely spaced objects

what are diffraction gratings used for?

-they can be used to measure the wavelength of light precisely -or also to separate light composed of different wavelengths

What happens when light passes through a single, small opening?

1. Light is diffracted 2. And a series of bright and dark bands appears

Who named the slight spreading of light around barriers- diffraction?

Grimaldi!

what did Thomas Young's (an English physician) experiment help do?

It enabled him to measure lights wavelength and also provided additional evidence of the wave nature of light

diffraction grating

an optical device with a series of thin, parallel grooves that creates an interference pattern of light

interference fringes

a pattern of light and dark bands on a screen, resulting from the constructive and destructive interference of light waves passing through two narrow, slowly spaced slits in a barrier

note:Wavelengths can be measured more precisely with a diffraction grating than with double slits

bang bang.

what happens when white light is used in a double-slit experiment?

diffraction causes the appearance of colored spectra instead of bright and dark bands, English? It is DIFFRACTED into the colors of the spectrum. (or colors of the rainbow preeedy)

the smaller the lens = the wider the...

diffraction patterns

when light enters the lens of a telescope, the lens ___________ the light

diffracts

the interference pattern produced by a diffraction grating has bright bands in the same locations caused by a __________ ______

double slit. But, the bands are narrower and the dark regions are broader

What did Francesco Grimaldi observe? hint:shadows

he observed that the edges of shadows are not perfectly sharp. bam

what can be used to measure the wavelength of light?

interference patterns

monochromatic light

light emitted of one wavelength

interference pattern

light passing through two closely spaced, narrow slits produces a pattern of dark and light bands on a screen

according to Huygens ( the guy who proposed a wave model to explain diffraction) all the points of a wave front of light could be thought as....

new sources of smaller waves. these wavelets expand in every direction.

note:The iridescent (rainbow-like) colors seen in many beetles comes from diffraction

now you know :)

the _____________ of the constructive and destructive interference bands depend on the wavelength of the light

position

note: Interference patterns are narrower and sharper than diffraction patterns

shabboooya!

note: In a diffraction experiment that uses monochromatic light, constructive interference produces a bright central band on the screen

shaboooya shabooooya roll call!

what do both interference and diffraction patterns depend on?

the wavelength of light(w), the width /separation of the slits(x,d) and the distance to the screen(L)

at the points where two crest meet...

the waves interfere constructively the light intensity increases creating a BRIGHT BAND

at the points where a crest and a trough meet....

the waves interfere destructively (cancelling eachother out) their is no light intensity creating a DARK BAND

what do diffraction gratings consist of?

they consist of large numbers of slits and produce narrow interference patterns

Equation Ed: Wavelength Using Double-Slit Interference

wavelength = xd/L x;separation of bright lines d;slit distance L;screen distance away

Equation Ed: Wavelength Using a Diffraction Grating

wavelength = xd/L = d x sin(theta)