Daily Challenge, 1/7

If light is made of waves and experiences interference, how will

the constructive and destructive interference appear to us?

Light shows Interference

Interference is the mutual effect (superposition principle) of two beams of light resulting in a loss of intensity in certain regions (destructive interference) and an increase of intensity of other regions (constructive interference)

Double Slit Interference – standing wave pattern similar to water wave tank

Interference in thin films – occurs due to reflection off front and back of film being slightly out of phase

http://sol.sci.uop.edu/~jfalward/lightinterference/lightinterference.html

Young’s Double Slit Experiment Thin Film Interference

Diffraction of Light Diffraction – the spreading of light into a region beyond an obstruction (happens on the scale of wavelength)

Diffraction Gratings – optical surfaces with many parallel, closely spaced grooves when a beam of monochromatic light is passed through… a principal image, along with less intense 1st, 2nd, etc. images, are produced

λ = d (sin θn) / mλ – wavelength of monochromatic lightd – grating constant, in length units m – order numberθn – diffraction angle, measured from principal image

Daily Challenge, 1/8

Check out the “rainbow glasses” and “snowflake glasses.”

Consider the physics of light discussed yesterday.

How do these glasses work?

Daily Challenge, 1/9

Minilab: (15 points) Use the diffraction gratings of known spacing to determine the wavelength of a laser. Sketch your experimental setup and show your work.

Remember λ = d (sin θn) / mλ – wavelength of monochromatic lightd – grating constant, in length units m – order numberθn – diffraction angle, measured from principal image

Physics Daily Challenge, 1/12

The specifications (accepted values) for groove spacing are 1.6 μm/groove on a CD and 0.7 μm/groove on a DVD.If you use a laser of known wavelength and the diffracted reflection images of the laser beam to calculate a groove

spacing of 15,300 Å for a CD, what is the absolute and relative

error of your measurement?