Refractive Index Flashcards
What is the practical for determining refractive index of a transparent block?
A source of light emits an incident beam. This travels through a transparent block. Measure the angle of refraction by drawing X’s along the emergent beam and calculate sin i and sin r against the normal. Plotting sin i against sin r will produce a graph where the gradient is found, showing refractive index. Uncertainties from sin i and sin r will show uncertainties in the refractive index.
What did Huygens find as evidence light travels as a wave?
Huygens provided evidence in the 17th century that light travels as a wave. He found that each point on a wave has little wavelets which are circular. When they meet in phase, they combine to produce a new wavefront. Wavelets out of phase will cancel out.
What happens when light travels through glass parallel to the normal?
When light travels through glass, it slows down and wavelength decreases in size so waves behind can catch parallel to the normal line.
What happens when waves travel through glass?
Waves travel faster in air, so the distance travelled decreases in glass as the speed decreases, as the refractive index is greater, so the wave travels through the same amount of space in the same time.
