P1 Topic 1 - Visible Light And The Solar System Flashcards
Name the two models of the solar system and explain them.
Geocentric model - Earth in the centre of the universe, other planets and Sun orbit it
Heliocentric model - Sun at the centre of the solar system, Earth and other planets revolve around. Proved by Galileo who saw that Jupiter had moons that did not orbit the Earth.
Define wavelength.
The distance from one peak to another.
Define frequency.
Frequency is how many waves pass a certain point per second. It is measured in Hz.
Define amplitude.
It is the height of a wave from the centre of a peak.
Define wave speed.
Wave speed is the speed of a wave. It is measured in m/s.
What are the two types of waves? Give some examples and describe the waves.
Transverse Waves - Light and other EM waves, S-waves, ripples on water, the vibrations are 90° to the direction of travel of the wave.
Longitudinal Waves - Sound and ultrasound, P-waves, the vibrations are along the same direction that the wave travels in.
What is reflection?
When a wave hits a boundary between two mediums, some of the energy bounces back.
What is refraction?
When a wave changes direction when it comes into contact with a different medium.
Explain the difference between a real image and a virtual image.
A real image is formed when the light from an object comes together to form an image on a screen.
A virtual image occurs when when the rays of light diverge so that the object appears to come from the opposite direction.
Explain what a converging lens does and what it is used for.
A converging lens is convex in shape and causes light to meet at one point and focus. This point is called the focal point.
What is the focal length of a lens?
Focal length is the distance from a lens to its focal point.
How does the distance of the object to the lens affect the image?
An object at twice the focal length (2F) produces a real, upside down image that is the same size as the object at 2F.
An object between 2F and F produces a real, upside down image that is bigger than the object beyond 2F.
An object closer than F produces a virtual, right-way-up image that is bigger than object and on the same side of the lens.
How does a refracting telescope work?
It is made up of an objective lens, which converges the light rays at its focal point, and an eyepiece lens, which take the real image formed by the objective lens and spreads them out so that they cover a larger area on your retina. This causes the image to seem magnified.
How does a reflecting telescope work?
A large concave mirror collects the light from an object on space and reflects them onto another smaller mirror which reflects the image again to an eyepiece lens which magnifies the image.
What is the formula for calculating wave speed using frequency and wavelength?
Speed (m/s) = Frequency (Hz) x Wavelength (m)
