L9 Wave nature of light

Question 1

what is a wave

Answer 1

a disturbance or change that propagates through available space or medium.

• energy transmitted
• particles from medium not transmitted
• oscillation returns to equilibrium

Question 2

5 types of waves

Answer 2

transverse, longitudinal, harmonic, mechanical, electromagnetic

Question 3

explain transverse and longitudinal waves

Answer 3

transverse: oscillation (V) perpendicular to propagation (H).
- eg: light/water waves

longitudinal: oscillation same direction (H) as propagation
- eg: sound/pressure waves

Question 4

explain intensity and energy in harmonic waves

Answer 4

(related to energy carried/delivered by wave)
-intensity for a harmonic wave is proportional to the square of the wave’s amplitude
(in light, perceived as brightness)

-energy for a harmonic wave is proportional to the square of wave’s amplitude

Question 5

explain mechanical waves

Answer 5

requires medium to transport their energy from one location to another
eg: sound cannot travel in vacuum

Question 6

explain electromagnetic waves

Answer 6

• travel at same velocity in vacuum (3x10^8 m/s)
• can be polarised and produce interference effects
• visible light wavelength (380nm-780nm) - activate receptors in the eye
• frequency of light waves remain same in diff media
• wavelength of light waves change in diff media