An object is placed at a distance of 15 cm from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
Given,
Object distance u = -15 cm
Focal length of convex lens f= 20 cm
Image distance v=?
We know that lens formula is:
Substituting the values in this formula 
v = -60 cm
i.e. 
Height of image = 4×height of object
● Image is formed on the same side of the object above the principal axis.
● It is virtual and erect.
● It is enlarged or magnified i.e. 4 times to the size of object.
15