Diffraction Gratting + Single Slit Flashcards
Why do diffraction gratings make sharper images? And what is the benefit I this?
There are more beams to ten force the interference pattern
This means a sharper image and more accurate messurments.
What is needed for a single slit to form a interference pattern?
A gap roughly the size of the wavelength
Monochromatic light
With monochromatic light what is the line of maximum brightness at the centre called?
Zero order line.
(For monochromatic light)
Ether side of the zero order lines there can be other lines. What are these lines called
1st order lines (nth)
What is the diffraction grating equation?
dsin@ = nlander
D = distance between slits
@ = angle to the normal made by diffraction grating.
N order of fringe
dsin@ = nlander
What does d,n and theta stand for?
D= slit spacing N = order of fringe @= angle of maxima with the normal .
In dsin@=nlander
If wavelength increases then..
then sin@ is greater and @ is bigger.
The higher the lights wavelength the more spread out.
In dsin@=nlander
If d is greater then, ?
Sin@ is smaller, @ is smaller the pattern is less spread out of the spacing between the gratings increases.
In dsin@=nlander
If sin@ is greater than 1
Then n does not exist because sin90 is 1.
What happens when you pass white light through a diffraction grating? Why?
Each order of fringe there is the spectrum.
Different wavelengths of light diffract at different rates. Dsin@=ny
When diffraction gratings are used for spectral analysis? What are the dark lines in the spectra called and why do thy appear?
They are called line absorption spectra and form due to elements on the stars surface absorbing that frequency.
What can diffraction gratings be used for?
Spectroscopy of light e.g light from stars
