Question

Find the position and nature of the image of an object 5 cm high and 10 cm in front of a convex lens of focal length 6 cm.   

Answer 1

Given:
Height of the object, h = 5 cm
Object distance, u =   -10 cm
Focal length, f = 6 cm
Applying lens formula, we get:
1/v -  1/u = 1/f (v = Image distance)
1/v - 1/( -10) = 1/6
or, v = 15 cm
Thus, the image is formed at a distance of 15 cm behind the convex lens (on the right side).
Now
Magnification, m = v/u = h'/h
m = 15/(-10)
m =-1.5
The value of magnification is negative; therefore, the image will be real and inverted.