2.3 Demonstrate understanding of lights and waves Flashcards
(27 cards)
What is the image formed by a concave mirror/convex lens when the object is beyond C?
Real Inverted Diminished
What is the image formed by a concave mirror/convex lens when the object is on C?
Real Inverted Same Size
What is the image formed by a concave mirror/convex lens when the object is between C and F?
Real Inverted Magnified
What is the image formed by a concave mirror/convex lens when the object is on the focal point?
No image forms
What is the image formed by a concave mirror/convex lens when the object is between F and the mirror?
Virtual Upright Magnified
Convex mirrors and concave lenses always have….
A negative focal point and and image that is always upright virtual and diminished
Which way does light bend when passing into a more dense medium (higher refractive index)?
Towards the normal
Which way does light bend when passing into a less dense medium (lower refractive index)?
Away from the normal
Why does refraction occur?
Because light changes speed as it crosses a boundary.
When does total internal reflection occur?
When light travels from a more dense medium into a less dense medium (n1 > n2)
What happens if Ø1 is less than Øc?
Light ray stil refracts
What happens if Ø1 is equal to Øc?
Refracted angle = 90º
No refracted light visable
Light is totally internally reflected
What happens if Ø1 is larger than Øc?
Light totally internally reflects
What are electromagnetic waves?
They are all transverse waves (Gamma, X-ray, UV etc)
Electromagnetic waves can show reflection refraction diffraction interference can pass through a vacuum slow down in dense mediums
What are longitudinal waves?
Sound waves
Direction of vibratiion is parallel to the wave movement. sound waves do not travel through a vacuum, speed up in denser mediums
How does a wave reflect from a fixed end?
Out of phase
how does a wave reflect from a free end?
In phase
What happens when a wave passes from a less dense medium into a more dense medium?
Acts as a fixed end so reflects out od phase
Wave also continues on in phase.
Amplitude of both waves decrease .
Wave in more dense medium travels slower and has a shorter wavelengh
Superposition of waves
If two waves meet then the resulting shape is equal to the wave shapes added together.
What happens when two waves meet exactly in phase?
Waves will constructively reinforce (anti-nodal point = reinforcement position, occurs when crest meets crest and where trough meets trough
sound = loud
Light = bright
What happens when two waves meet exactly out of phase?
Waves will cancel as the deconstructively interfere. (nodal point = cancelation position, occurs when crest meets trough)
Sound = quiet
Light = darkness
What happens when a wave is reflected?
Wave length doesnt change
incident angle = reflected angle
Reflected wave is in phase
What happens when a wave is refracted?
- deep water = less dense
- shallow water = more dense
Vshallow < Vdeep
WLshallow < WLdeep
Frequency does not change
What is diffraction?
The bending of waves around corners as the pass the edge of a barrier. No change in wave length speed or frequency unless depth changes
Diffraction decreases as wave length shortens and frequency decreases
Light diffracts poorly as it has a short wavelength and high frequency
Sound diffracts well
