The size of the image relative to the size of the object is another
important quantity to consider We define linear magnification (m) as the
ratio of the height of the image (h¢) to the height of the object (h):
m = 
h
h
′
(9 8)
h and h¢ will be taken positive or negative in accordance with the accepted
sign convention In triangles A¢B¢P and ABP, we have,
B A
B P
BA
BP
′
′
′
=
With the sign convention, this becomes
Rationalised 2023-24
Physics
226
–
–
h
v
h
u
′ = –
so that
m = 
–
h
v
h
u
′ =
(9