Instructions : Drag and drop the candle at different positions to see how the lens modifies the light beam's path to form different images.
What is a Concave Lens?
A concave lens is a piece of round glass that is thinner at the centre than at the edges. It bends the rays of light passing through it away from each other i.e. diverges them. Opticians use concave lenses to correct nearsightedness. They are also used in flashlights to magnify the light, and can be found in door viewers or peepholes.
What is Principal Focus?
When parallel rays of light pass through a concave lens, the refracted rays appear to diverge from one point which is called the principal focus.
What is Focal Length?
The distance between the center of the concave lens and its principal focus is called its focal length.