An object of height 4 cm is placed at a distance of 15 cm in front of a concave lens of power, −10 dioptres. Find the size of the image.
Object distance u = -15 cm
Height of object h = 4 cm
Power of the lens p = -10 dioptres
Height of image h' = ?
Image distance v = ?
Focal length of the lens f = ?
We know that:
⇒ `f=-0.1m =-10 cm`
From the lens formula, we have:
Thus, the image will be formed at a distance of 6 cm and in front of the mirror.
Now, magnification m =`v/u=(h')/h`