Diffraction & Interferance of Light
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The students are looking at the light bulb (as seen on the above
left) through a pin hole, 2 pin holes, and 4 pin holes made
on an aluminium foil. When light is viewed through these tiny holes,
a diffraction pattern can be seen. When the light source is viewed
through 2 and 4 pin holes, a bright circular patch with coloured
rings is seen. This is a diffraction and internference pattern.
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Students
hard at work on the topic of Einstein's Photo-electric Effect:
hf = hfo + 1/2 mv2
and De Broglie's Equation
(Momemtum)(wavelength) = h
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JC2 Physics students learn about polarisation
of transverse light waves. They are looking at the polarised
reflected light from a poster with a glass cover. The plane polarised
light of reflection can be easily 'cut out' by rotating the polariser.
This technique is used by photographers who are able to take good
photographs of exhibits inside a glass casing on display, and also
of fishes swimming just below the water surface in a shallow pond.
Without the use of polariser, which can be attached to the camera
lens, the exhibits and the fishes will not be clear, due to reflected
rays from the glass casing and the water surface. |
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