Question

A convex lens forms the image of sun at :

• A. Focus
• B. Centre of curvature
• C. Between focus and centre of curvature
• D. No image is formed

Hint:

For any lens or mirror, light rays coming from an object at infinity (like the Sun) are considered parallel. These parallel rays, after refraction/reflection, converge at the focal point of the lens/mirror.

Answer 1

The Correct Option is A

Step 1: Understand the nature of light rays from the Sun.
The Sun is an extremely distant object. For practical purposes in optics, light rays coming from a very distant object are considered to be parallel to the principal axis when they reach a lens or mirror. Step 2: Recall the properties of a convex lens for parallel rays.
A convex lens is a converging lens. When parallel rays of light (like those from the Sun) incident on a convex lens, after refraction through the lens, they converge at a single point on the principal axis. This point is known as the principal focus (or focal point) of the lens. Step 3: Determine the image location.
Since the parallel rays from the Sun converge at the principal focus after passing through the convex lens, the image of the Sun is formed at the focus. This image is real, inverted, and highly diminished (a point-like image). Step 4: Compare the conclusion with the given options.
The image of the Sun formed by a convex lens is at its focus. This matches option (1). $$(1) Focus$$