Question

A convex lens produces an inverted image of size 1.4 cm The size of object is 0.7 cm

1. What is magnification in the case

2. What is the nature of image

3. If the object is at distance 30 cm from the lens calculate focal length of the lens

Answer 1

1. m = \(\frac{h_0}{h_1}\)  \(\frac{-1.4}{0.7}\) = -2

2. Real, inverted, magnified 

3. m = \(\frac{f}{f+u}\) ; -2 = \(\frac{f}{f+-30}\) ,f = 20 cm