Question

A photographer uses a telephone lens (allows the camera to zoom in) to take a photograph of a 50m high building that is 1000m away. A real image produced is 2.0 cm high. What is the focal length of the lens?

Answer 1

The focal length of the lens is 0.0202m or 20.2mm.

Step-by-step explanation:

To find the focal length of the lens, we can use the lens formula: 1/f = 1/v - 1/u, where f is the focal length, v is the image distance, and u is the object distance.

In this case, the object distance is 1000m (given) and the image distance is 0.020m (converted from 2.0 cm).

Substituting the values into the formula, we get: 1/f = 1/0.020 - 1/1000. Solving for f, we find that the focal length of the lens is 0.0202 m or 20.2 mm.