8 Determine the Wavelength of Light Flashcards
what safety precautions should be taken when operating a laser
-never look directly at the beam
-ensure no reflective surfaces are in the lasers vicinity
-display a warning notice so other know a laser is in use
why should the screen you display the interference on have a matt finish
to reduce the intensity of the reflection of the beam, potentially into someones eye therefore reducing the harm
what does it mean if two light sources are coherent
same wavelength and constant phase difference
what is monochromatic light
light of a single wavelength (or frequency)
how is a diffraction grating space calculated
it is the reciprocal of the number of Ines per meter
how can the angle from the centre to a higher order line be calculated
the distance from the diffraction grating to the screen and the distance from the centre to the higher order line can be used using trig
how does the diffraction pattern from a double slit compare to one from a diffraction grating
as the number of slits increases the pattern becomes sharper and the fringes become brighter. this is because more rays are reinforcing the pattern.
what is a use of diffraction gratings
can be used instead of a prism to analyse spectra
what is the nature of light emitted by a laser
light produced is monochromatic, coherent light that is collimated
describe the interference pattern produced if white light is passed through the diffraction grating
a central bright white fridge will be produced. all other fringes will consist of a spectra with blue closest to the inside and red closest to the outside
why does the interference of white light consist of a spectra
white light is a mix of all colours and so consists of lots of different wavelengths. each wavelength will be diffracted by a slightly different amount resulting in a spectra.
why do bright fringes form on a screen when light is passed through a diffraction grating
light diffracts as it passes through the slits and these waves interacts and undergo super position where constructive and destructive interference occurs, when in phase fringes form due to constructive interference.
