5.1-5.11 Rays, Lens and Electromagnetic spectrum Flashcards
In ray diagrams what do arrows show?
The direction at which light is travelling
What is the normal?
An imaginary dashed line which is perpendicular to the surface and from which all angles are measured from
Which ray is the incident angle the angle of?
.The entering ray
Which ray is the reflected ray the angle of?
.The exiting ray
If entering a denser material what happens to the light ray?
It bends towards the normal
If entering a less dense material what happens to the light ray?
It bends away from the normal
What is the law of reflection?
When rays are reflected the angle of reflection is equal to the angle of incidence
What is the critical angle?
The angle at which total internal reflection begins to happen
What is total internal reflection?
When light is moving from a denser medium to a less dense one instead of being refracted all of the light is reflected
What’s the difference between specular and diffuse reflection?
.Specular is when light hits a smooth surface-diffuse is when light hits a rough surface and the incident ray s reflected at many angles
What do all of the colours together make up?
White light
True or False? Each colour has its own wavelength
True
What is the focal length?
Distance between lens and focal point
If you had a shorter focal length what happens to the power?
Greater power
What does a thicker lens do to focal length?
Shorter focal length
The thicker the lens the greater the …?
Power
What are concave lens used to fix?
Short sightedness
What are convex lenses used to fix?
Long sightedness
What happens to the light in a concave lens?
Spreads light outwards
What happens to light in convex lenses?
It focuses the light inwards
Where do real images appear to come from?
The opposite side of the lens to the object
Where do virtual images appear to come from?
The same side of the lens to the object
