Correct Option
The correct option is (c).
Explanation
The burning of paper using sunlight involves the concentration of solar energy onto a small area using optical devices. This phenomenon relies on the convergence of parallel light rays coming from a distant source (infinity) to a specific focal point.
Statement-wise Analysis
- Statement 1 is Correct: A concave mirror is a converging mirror. When parallel rays of sunlight strike a concave mirror, they are reflected and converge at the principal focus. The concentration of light energy at this focal point generates sufficient heat to burn paper placed there.
- Statement 2 is Incorrect: A convex lens is a converging lens, not a diverging one. It refracts parallel rays of sunlight inwards, bringing them to a focus on the other side of the lens. Therefore, a convex lens can also burn paper by focusing sunlight. It is the concave lens that diverges light.
- Statement 3 is Correct: The bright spot formed on the paper represents the point where the light rays actually meet after reflection or refraction. Since the rays physically converge at this point, the spot is a real image of the Sun formed at the focus of the mirror or lens.
Key Takeaway: Both concave mirrors and convex lenses are converging optical devices capable of focusing parallel light rays from infinity to form a real, point-sized image at their focus, generating intense heat.