Question

A lens which forms a real image has a power of +12.5 D. The focal length of the lens is:

Options

• 16 cm

• 12 cm

• 8 cm

• 20 cm

Answer 1

8 cm

Explanation:

Using $$\text{f} = \frac{1}{\text{P}}$$

$$= \frac{1}{12.5}$$

= 008 m

= 8 cm

The positive power indicates a convex lens, which can form a real image.