Understanding
Light
Light
What is the speed of light?
300 million metres per second (300,000,000 m/s).
What is reflection?
Reflection occurs when light hits a smooth surface, such as a mirror.
What is refraction?
The change in direction of light when it moves from one medium to another.
What do lenses do to light?
They refract light.
What device disperses white light into its component colours?
A prism.
What type of object produces its own light?
A luminous object
Give an example of a surface that reflects light well.
A mirror.
Why does light refract?
Because its speed changes when it moves between different media.
Which type of lens is thicker in the middle?
Convex Lens
What is the name of the band of colours produced when white light is split up?
The spectrum.
What is the name of a material that allows most light to pass through it?
A transparent material.
What is the law of reflection?
The angle of incidence equals the angle of reflection.
What happens to light when it enters a more dense medium?
It bends towards the normal.
Which type of lens has no focal point?
Concave Lens
What are the three primary colours of light?
Red, green and blue.
In a ray diagram, what is the dotted line at 90° to a surface called?
The normal line.
From what line are reflection angles measured?
The Normal Line
What happens to light when it enters a less dense medium?
It bends away from the normal.
What happens to light passing through a convex lens?
It is refracted to a focal point.
What does ROYGBIV stand for?
Red, Orange, Yellow, Green, Blue, Indigo, Violet.
Explain how a shadow forms.
A shadow forms when light travelling in straight lines is blocked by an opaque object.
If light strikes a mirror with an angle of incidence of 35°, what is the angle of reflection?
35°. The angle of incidence is always equal to the angle of reflection.
Why does an object under water appear closer to the surface than it really is?
Because refraction changes the direction of light leaving the object, making it appear nearer the surface.
Name the two convex lenses found in the human eye.
The cornea and the lens. They help focus light onto the retina.
Why does a red apple appear red?
Because it reflects red light and absorbs all the other colours.