Can light travel around corners…? Light through One Slit Yes! No..!
<ul><li>Light undergoes superposition when travelling through: </li></ul><ul><ul><li>2 slits </li></ul></ul><ul><ul><li>A diffraction grating (we call this a transmission grating – it let’s light through) </li></ul></ul>To review
To finish off the wave topics, we need to discuss: - How spectra can be used to analyse spectra produced by stars (wavelengths of radiation emitted) - How light behaves when it goes through a single gap - How phasors can explain superposition
At certain angles the particular wavelength constructively interferes – all other wavelengths have destructively interfered. At this angle, only the one colour is seen. Grating
Transmission v Reflection Because grating absorb radiation (light), reflection gratings can be used for other wavelengths. These follow the same principle but for reflections
Single Slit Diffraction <ul><li>We know that water travels through a gap in a harbour wall – but not like this… </li></ul>
Single Slit Diffraction <ul><li>More like this… </li></ul>But what about light….?
Pattern Through Grating Pattern Through Single Slit
Note - for small angles of , Sin approx = But what does this mean….?
Resolution <ul><li>When can you see: </li></ul><ul><ul><li>2 stars that are close together as 2 stars? </li></ul></ul><ul><ul><li>The head lights of a car as 2 headlights? </li></ul></ul>Seen as 2 light sources Seen as 1 light source