An object is placed 60 cm from a convex lens of focal length 20 cm. How far from the lens is the image?

Answer and explanation

Correct answer: A. 30 cm

  1. Step 1: Lens formula: 1/f = 1/u + 1/v (real-is-positive). Step 2. 1/v = 1/20 − 1/60, so v = 30 cm. Answer: 30 cm. Why not the others: 15 cm is what you get if you use 1/v = 1/f + 1/u. 40 cm is what you get if you subtract the distances. 80 cm is what you get if you add the distances.

Practise more Physics.

Free questions with an explanation for every one, and full timed Uzbekistan National Certificate (Milliy sertifikat) mock tests.

All Physics questionsTake a mock test

More Physics questions