Topic 1 - Visible light and the solar system Flashcards
What is the geocentric model?
Everything orbited the earth.
What is the heliocentric model?
All planets orbit the sun, which is at the centre of the universe.
who thought of the heliocentric model?
Copernicus
What evidence helped support the heliocentric model?
Galileo discovered moons orbiting jupiter which showed that not everything was orbiting the earth proving the geocentric model wrong
what does the current model state?
all the planets in our solar system orbit the sun but these orbits are elliptical rather than circular
What did early astronomers use to study the stars
naked eye but this was only useful for mapping things positions
What are the advantages of telescopes?
magnify images so they can be seen in more detail.
see objects at larger distances
help learn what the universe is made of.
Can be sent into space to avoid light being absorbed by the atmosphere
Can use cameras
What advantages are there for using digital cameras with telescopes
Can ‘zoom in’ to see things in more detail
makes it easier to monitor an object by taking pictures at different times.
Can see faint objects by allowing a long exposure time.
What is wavelength
the distance from one peak to the next
What is frequency
how many complete waves there are per second. Measured in hertz
What is amplitude
The height of the wave from the midline to the peak
What do waves transfer
energy and information without transferring matter
What is a transverse wave
the vibrations are perpendicular to the direction of travel
give examples of transverse waves
EM waves
S-Waves
What is a longitudinal wave
the vibrations are parallel to the direction of travel
give examples of longitudinal waves
Sound
P-Waves
What is an oscilloscope
shows things as transverse waves even sound
what is the relationship between the angle of incidence and the angle of reflection when a wave is reflected
i = r
Why is light reflected
when theres a change in destiny some of the wave is reflected
What happens when a wave is refracted?
the material its travelling in changes density so the speed changes and sometime the direction of the wave
What happens when a wave goes into a denser material
it slows down and the direction moves towards the normal
What is a real image
When the light from an object comes together to form an image on a ‘screen’
What is a virtual image
When rays of light are diverging so the light from the object appears to be coming from a completely different place
Give an example of a virtual image
Magnifying glass
Reflection
What is a converging lens
convex (blues outwards)
Causes parallel rays of light to move together (converge) and focus
Focal point is where rays hitting the lens parallel to the axis meet
Image is flipped
Describe an experiment to find the focal length of a lens
Clamp lens to one end of a track, clamp piece of white card further down the track.
Set up the equipment near a window with the lens directed at a distant object.
Move card along the track until the image is focused and clamp it so it doesn’t move.
Measure the distance between the centre of the lens and the card and thats the focal length
Describe a refracting telescope
Objective lens focuses the rays of light to form a real image at the focal point. the eyepiece lens then magnifies the image so you can see it
describe a reflecting telescope
A large concave mirror (primary mirror) collects the light and reflects the light onto a smaller concave mirror in front of the focal point. The smaller mirror (secondary mirror) reflects light through a hole in the centre of the primary mirror and an eyepiece lens magnifies the image so you can see it.
