Question

(a) an object is placed at a distance of 15cm from a convex mirror of focal length 20 cm.finnd the position and nature of the image

Answer 1

focus = focal length / 2

= 20 / 2

= 10

but object is placed on 15 cm

so position of object is between the centre of curvature and focus

nature of image is virtual , erect & diminished

Answer 2

object distance (u) = 15cm
focal length(f)=20cm
image distance( v)=?
by mirror formula,
1/v+1/u=1/f
1/v=1/f-1/u
=1/20-1/15
=3-4/60
= -1/60
1/ v =-1/60
v=-60
image distance=60cm
nature =virtual and erect