Light Physics gcse Flashcards
what is the law of reflection
Its when a ray of light reflected from a plane surface, The angle of reflection is equal to the angle of incidence
What are the properties of an image in a plane mirror
- Laterally inverted
- Same size
- Same distance
- Virtual image
What is the definition of Virtual image
It is an image that cant be focused onto a screen
What happens to light traveling into a glass block
The light bends towards the normal (slows down)
What is the definition of Refracted
when something Changes directions
What is dispersion
When white light is separated into 7 colours using glass prism
what are the 7 colours of the visible spectrum in order
Red Orange Yellow Green Blue Indigo Violet
Why does dispersion happen
As all colours of the visible spectrum travel at the same speed in a vacuum (or air) But colours have different frequencies therefore different wavelength meaning they slow down by different amounts when entering glass so they refract at different amounts
What colour has the biggest wavelength
Red
What colour bends the most through prism
Violet
What colour slows down the least when passing through a prism
Red
What colour slows down the most when passing through a prism
Violet
Define the critical angle
When the angle of incidence is in an material (air, glass), the angle of refraction in air is 90 degrees
What is in the critical angle for glass
42 degrees
What are the uses for total internal reflection
Periscopes
Reflectors
What is total internal reflection
When the ciritical angle is over 42 and there is no refraction.
What are fibre-optic used for
Used in communication for carrying signals.
An endoscope.
Advantages and disadvantages of communications (fibre optic)
Advantages- Carry more information than copper at the same diameter.
Disadvantages- Signal needs to be boosted every few km
Advantages and Disadvantages of endoscopy (Fibre optic)
Advantages- See inside patients body without needing large hole.
Disadvantages- May be uncomfortable, cause sore throat
what happens when the angle of incidence is above 42 degree
Total internal reflection
