Correct Option
The correct option is (c).
Explanation
A lens is a transparent optical device bounded by two surfaces, at least one of which is curved. Lenses manipulate light through the process of refraction, bending light rays to either converge or diverge depending on the shape of the lens.
Statement-wise Analysis
- Statement 1 is Incorrect. A lens that is thicker in the middle and thinner at the edges is a convex lens (also known as a converging lens). The statement describes a lens thinner in the middle as convex, which is factually wrong.
- Statement 2 is Correct. A lens that feels thinner in the middle than at the edges is a concave lens (also known as a diverging lens). This physical characteristic is the primary structural distinction between concave and convex lenses.
- Statement 3 is Correct. Lenses are by definition transparent objects made of materials like glass or plastic. Their primary function is to refract light, altering the path of rays passing through them to form images.
Key Takeaway: Structurally, a convex lens is thicker at the center (converging nature), whereas a concave lens is thinner at the center (diverging nature). Both operate on the principle of refraction.