Learn about and revise lenses and their power, real and virtual images, and ray diagrams with GCSE Bitesize Physics.

Concave lens formula is used to determine the position and nature of the image formed after a ray of light passes through the concave lens. The formula is known as the lens formula.

Lenses are used in cameras, telescopes, binoculars, microscopes and corrective glasses. A lens can be converging (convex) or diverging (concave).

We compare and contrast concave and convex lenses by drawing ray diagrams. In this Closer Look segment on Lenses, we compare and contrast concave and convex lenses by drawing ray diagrams and ...

Question 10: An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.

If focal length = f = ‒ 50 cm, then P = 100/ f = 100/ −50 = −2D, lens is concave. Question. 38 A student focused the image of a candle flume on a white screen using a convex lens.