P1 - Topic 1 - Reflection And Refraction / Lenses / Telescopes Flashcards
How can waves be reflected?
When a wave hits a boundary between one medium and another, some of the energy is reflected
Why can you sometimes see your reflection in puddles?
Light is reflected back at you
The angle of reflection is the same as what other angle?
The angle of incidence
‘r’ represents what angle?
Angle of reflection
‘i’ represents what angle?
The angle of incidence
Waves can’t be reflected. True or false?
False - they can be reflected
Why is the light reflected?
Because of the change in density, whenever a wave reached a medium with a different density, some of the wave is reflected at the boundary
Do waves travel at the same speed or different speed in substance which have different densities?
Different speeds
In denser media do EM waves usually travel slower or faster?
Slower
Do sound waves travel faster in denser substances?
Yes
What happens when a wave crosses a boundary between two substances (from glass to air) ?
It changes speed
If a wave hits the boundary face on what happens?
It slows down but carries on on the same direction
If a wave meets a different medium at an angle what happens?
That part of the wave huts the denser layer first and slows down while he the other part carries km at the first, faster speed which causes the ace to change direction
If light is passim from the air into the glass (a denser medium) what cause the light Ray to bend towards the medium?
When the light transfers from the air to the glass it slows down causing It to refract
When does the light bend away from the normal?
When the light reaches the glass to air boundary on the other side of the a down its passing into a less dense medium so it speeds up and bends away from the normal
What kind of Mage is actually there and wha kind of image is not actually there
Real image = actually there
Virtual image = not actually there
What is a real image?
It is where the light from an object comes together to form an image on a ‘screen’
What is a virtual image?
It is when the Rays are diverging so the light from the object appears to be coming from a completely different place
When you look in the mirror do you see a real or virtual image and why?
Virtual image of your face because the object appears to be behind the mirror
When you look at an object through a magnifying lens why do you see a virtual image?
The image looks bigger and further away than the object actually is
What are converging lenses used for?
To focus light
What does a converging lens cause parallel Ray’s of light to do?
Converge (move to) a focus
What is the line called that passes through the middle of lens
The axis of the lens
What is the focal point?
Where the Rays hitting the lens parallel to the axis meet
Each lens has a focal point where?
In front and the las and one behind
What is the focal length?
The distance from the lens to its focal point
What lenses does a refraction telescope use?
Two converging lenses
What two converging lenses is a refracting telescope made up of?
An objective lens and an eyepiece lens
Do refracting telescopes form virtual or real images?
Real images
