The next section deals with reflection
In curved mirrors
In Fig 2 the
object is
between F and
2F. The image
Is further
away,
Enlarged,
inverted
and real
A further ray can be drawn passing though the focal point on the object side of the lens.
This ray passes through the lens and leaves on a path parallel to the principle axis. If the
drawing is accurate this ray should meet the other two rays at the point of intersection.
It is possible to predict the size and position of of an
image in a convex lens by constructing an accurate ray
diagram
In Fig 1 the object is at 2F. The image is at 2F on the
other side,same size as the image, inverted, same distance
away and real.
A ray from the top
of the object drawn
parallel to the
principle axis (centre
line) goes through the
lens and through the
focal point on the
other side of the lens.
Another ray can be
drawn straight
through the centre of
the lens. Where the
two rays meet is the
position of the image
In Fig.3 the
object is beyond
2F. The image is
nearer,diminished,
inverted and real
A real image is on the opposite side of the lens to the object
and can be projected onto a screen and is formed by real
rays
A virtual image is on the same side as the object and cannot
be projected. Virtual images are formed by virtual rays