WAVES (HL)
THE CRITICAL ANGLE
When light goes from a less dense medium to a denser medium, light bends towards the normal.
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If incident angle critical angle, then the angle of refraction is exactly 90 degrees.
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If angle is greater than the critical angle, then light will reflect, not refract.
DIFFRACTION PATTERNS
DOUBLE SLIT DIFFRACTION
If both slits are of non-negligible width
SINGLE SLIT DIFFRACTION
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Bright fringe in centre surrounded by dark fringe and then bright fringe
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Intensity will decrease the further away you go from the central maxima
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Pattern occurs due to the wavelets on the wave. Every point on a wave is a source for another wave.
STANDING WAVES
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Combination of two waves moving in opposite directions with the same amplitude and frequency
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Particles are going to be still (they will not move, only oscillate) and there will be no transfer of energy
No. of nodes = no. of antinode + 1
Antinodes = no. of loops
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NODAL LINE – A set of points where waves interfere destructively and that remain at rest in the equilibrium position.
ANTINODAL LINE – A set of points where waves interfere constructively and that have maximum displacements in the medium.
CLOSE-OPEN END
CLOSE-CLOSE END
OPEN-OPEN END
Rayleigh Criteria (only works for circular aperture)
DIFFRACTION BY THIN FILM
DIFFRACTION GRATING
