Answer :
A lens which is thicker at the edges and thinner at the centre is known as concave lens. or a lens such that a parallel beam of light passing through it is caused to diverge or spread out diverging lenslens,lens system,lense- a transparent optical device used to converge or diverge transmitted light and to form images
Concave lens is a spherical lens. Convex lenses are thicker at the middle and thina t the edges. Rays of light that pass through the lens gets converged. A convex lens is also known as a converging lens.When parallel rays of light pass through the convex lens the refracted rays converge at the principal focus.
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