LENSES
CONVEX LENSES
• Convex lenses cause light rays to
converge
• The focal point is the place where
all of these rays converge, and the
focal length is the distance this is
from the centre of the lens
• Convex lenses are used in
magnifying glasses, cameras,
microscopes and eyeglasses
CONCAVE LENSES
• Concave lenses cause light rays to
diverge or spread
• The focus is on the other side of
the lens, at the pint where the
divergent rays appear to have
come from – it is a virtual focus
• Concave lenses are used for
short-sightedness, torches,
telescopes and binoculars