The correct option is (a).
Explanation
Lenses are transparent optical media bounded by spherical surfaces that refract light. The behavior of a lens-whether it converges or diverges light-depends on its shape and the refractive index of the material relative to the surrounding medium.
- Statement 1 is Correct: A convex lens is thicker at the center than at the edges. When parallel rays of light pass through it, they are bent inwards towards a principal axis and meet at a specific point known as the focus. Therefore, a convex lens converges the light falling on it.
- Statement 2 is Incorrect: A concave lens is thinner at the center than at the edges. When parallel rays of light pass through it, they are bent outwards, spreading away from the principal axis. Therefore, a concave lens diverges the light, rather than converging it.
- Statement 3 is Incorrect: Since a convex lens brings light rays together to a point, it is technically termed a converging lens. Conversely, a concave lens is termed a diverging lens.
Key Takeaway: A convex lens acts as a converging lens, focusing light to a point, whereas a concave lens acts as a diverging lens, spreading light rays apart.