Convex and concave lenses

Where can convex lenses curve?

Outwards.

What do convex lenses make?

Parallel rays of light converge at a point.

What’s the focal length?

The distance from the centre of the lens to the principal focus.

What’s the principal focus in convex lenses?

The point where refracted rays of light come together.

Where can concave lenses curve?

Inwards.

What do concave lenses make?

Parallel rays of light diverge (so they appear to come from a point.

What’s the principal focus in concave lenses?

Point where refracted rays of light appear to come from.

What can images be formed by convex lenses?

Convex lenses can be either real or virtual.

What can real images be?

Projected onto a screen.

What can virtual images be?

Appear to come from behind the lens.

What can images formed by concave lenses be?

Always virtual.

What can images formed by a lens be?

Magnified or diminished and upright or upside down (inverted).

What can the magnification of an image be calculated?

Magnification= image height/object height.

Why does magnification have no units?

It’s a ratio.