P1 topic 1 - Visible light and the solar system Flashcards
What makes an image real?
If it can be projected on a screen it’s real, if not it’s virtual.
What is the focal length?
The distance from the screen and the lens.
Types of transverse waves?
S-waves
Electromagnetic spectrum
Vibrations at 90 degrees to the direction of travel of the wave.
Types of longitudinal waves?
P-waves
Sound
Vibrations are along the same direction as the wave is travelling.
Compressions and rarefractions.
What do waves carry?
Energy and information.
What is the amplitude?
The distance from the line to the top of the wave.
What is frequency?
The number of waves passing a point every second.
What is the role of the eyepiece lens?
Eyepiece lens magnifies the real image formed by the objective lens.
What are the advantages of reflecting telescopes?
It’s easier to make big mirrors than big lenses so reflecting telescopes can be larger and see more distant stars.
What is the geocentric model?
Everything in the solar system orbits the earth which is in the centre. The earth is orbited in perfect circles.
What is the heliocentric model?
The earth and all the planets orbit the sun, which is at the centre of the universe. Still perfect circle orbits.
Galileo’s observations?
He was observing Jupiter with a telescope when he saw three stars in a line near the planet. When he looked again he noticed they had moved the wrong way in the sky. These stars never moved away from Jupiter and were carried along with it, he realised these were moons. This proved that not everything orbits the earth and proverb the geocentric model wrong.
What are the advantages of now using telescopes?
They magnify images, so distant objects can be seen in more detail. You can see objects at a larger distance. They have discovered many new objects and helped add to our knowledge of the universe.
What are the disadvantages of telescopes on earth?
The atmosphere gets in the way because it absorbs the light coming from space. Light and air pollution also make it difficult.
What are the advantages of getting photographs from telescopes?
It allows you to zoom in and look at the objects in more detail. It makes it easier to monitor by taking pictures at different times. You can also compare observations. You can see faint objects by allowing a long exposure time so you collect more light.
