Nature of Waves Flashcards
What would happen if two loudspeakers from the same output of an oscillator were placed a meter apart?
There would be alternating loud and quiet areas in front of them.
What is constructive interference?
The two waves meet in phase (crest and crest), it makes the wave have more energy. The path difference between the two sources is a whole number of wavelength.
What is destructive interference?
The two waves meet out of phase (crest and trough), it makes the wave cancel out. The path difference between the two sources is an odd number of half wavelengths.
What is interference between light waves caused by?
When it diffracts when it passes through narrow slits. Bright bands are constructive interference, dark bands are destructive interference.
Why do the slits have to be very narrow?
The wavelength of light is 0.0004 to 0.0006 mm so the slits have to be a similar size to get the maximum amount of diffraction.
How do electromagnetic waves travel in all directions?
Oscillations occur in all directions at right angles to the wave direction.
How does light become polarised?
Light is polarised if the oscillations are only in one direction at a right angle to the wave direction. Polaroid sunglasses stop oscillations in al but one direction perpendicular to the wave direction which reduces the amount of light passing through.
What did Newton think light was and how was he proved wrong?
He thought light was a particle but if it was a particle it should move through a denser medium faster rather than slower unlike Huygens who suggested light was a wave.
