Section 2 - Electromagnetic Spectrum and light Flashcards
What type of wave are Electromagnetic waves?
Transverse
What happens when you increase the frequency of an electromagnetic wave?
You increase the energy transferred
List the electromagnetic waves
Radio Waves Micro Waves Infra Red Visible Light Ultra Violet X-Rays Gamma Rays
What does red and green light make?
Yellow light
What does red and blue light make?
Magenta
What does blue and green light make?
Cyan
What do filters do?
Let through some colours of light through, and absorb the others
What is black?
The absence of colour
What is white light?
All of the colours of light combined
How do we see light?
By light reflecting off the object and into our eyes. The object absorbs all of the light that is not the same colour as it.
Why do waves refract when changing medium?
Waves move at different speeds in materials with different densities, so when a wave changes medium it changes speed. When the wave hits the new medium at an angle, it causes a change in speed, this change of speed causes a change in direction.
What affects how much a wave refracts?
The shorter the wavelength the more it refracts
When a wave refracts and it slows down, which way does it bend?
Towards the normal
When a wave refracts and it speeds up, which way does it bend?
Away from the normal
What happens when a wave enters a new medium along the normal line?
It will change speed but will not refract
What is a converging lense?
A converging lense bulges in the middle. Causing parallel rays of light to converge on a principal focus
What is a diverging lens?
A diverging lens caves outwards. It causes parallel rays of light to converge outwards.
What is the focal length of a lens?
The distance between the centre of the lens and the principal focus
What affects the focal length of a lens?
The more powerful the lens, the shorter the focal length. Because the lens is making the rays of light converge more.
What is the principle focus of a converging lens?
Where the rays hitting the lens parallel to the axis all meet
What is the principle focus of a diverging lens?
The point where rays hitting the lens parallel to the axis appear
When is a real image formed by a lens?
When the light rays passing through the lens come together to form the image.
When is a virtual image formed by a lens?
When the light passing through the lens creates an image that appears to be in a different place than the rays are coming from. (For example the image appears smaller that it should.)
