P11: Lenses and The Eye Flashcards
Concave (Diverging) Lens
Concave (Converging) Lens
Uses of a convex lens
Magnifying Glass, In a camera to create a clear image of a far off object.
Uses of a concave lens
To correct short sightedness.
Focal Length
The distance from the centre of a lens to where the light rays focus (or, in the case of a concave lens, appear to diverge from.)
Real Image, from a convex lens.
Virtual Image, from a concabe lens
Magnification of an image =
Image height/ Object Height
How to construct a real image/converging lens diagram
How to construct a virtual/Converging lens diagram
How to construct a virtual/Diverging lens diagram
How does a camera work?
What does ‘real is positive’ mean?
Real images are given positive focal lengths in the formula, virtual negative.
1/focal length =
1/distance from object to lens + 1/distance from lens to image
(1/u + 1/v = 1/f)
A diverging lens…
… always gives a virtual image.