Light Flashcards
How do you draw a convex lens light diagram?
- Draw a line from top of small light line across to lens perpendicularly.
- Draw a line to centre of lens line and across the other side.
- Draw a line from top of lens line through f point on other side.
- Where lines meet is image.
- Large line is enlargement. Line on other side is inversion.
How do you draw a concave lens light diagram?
- Draw a line perpendicularly from top of light line to lens line.
- Draw line from top of object, through the centre of the lens.
- Draw a line from the principal focus to the point where the perpendicular line ends. The point where it crosses is the image.
What is reflection from a rough surface called?
Diffuse reflection.
How do you measure the angle of refraction?
From the refracted ray to the normal line.
What happens to light moving from a high density object to a low density object?
When light travels from a more dense medium to a less dense medium, it moves away from the normal line.
What does a white surface reflect (colour)?
All colours.
What light is relflected from a red surface?
Red light only.
What happens to light with convex lenses?
It converges to a point, called the principal focus.
What is the focal length?
The distance from the principal focus to the centre of the lens.
What happens to the image if the object is further away from the lens than the principal focus?
The image is inverted.
What happens to the image if the object is closer to the lens than the principal focus?
A virtual image is formed behind the object. It is now magnified.
How do you calculate magnification?
Image height / object height.
What happens to light with a concave lens?
It diverges away from a point. The rays come from the principal focus and go outwards.
What image is always produced by a concave lens?
A virtual image.
With a convex lens, if the object is in front of the principal focus, what happens to the image?
It becomes a magnified, virtual image.
