The refractive index of the material of a concave lens is . It is immersed in a medium of refractive index ₁ . A parallel beam of light is incident on the lens. The path of the emergent rays when ₁> is:

Step-by-step solution

If a lens of refractive index is immersed in a medium of refractive index ₁ , then its focal length in medium is given by 1 f _ m = ( _ m _l-1 ( 1 R ₁ )- 1 R ₂ ) If f _ a is the focal length of lens in air, then aligned & 1 f _ a = ( _ a _l-1 ( 1 R ₁ - 1 R ₂ ) . & f _ m f _ a = ( _ a _l-1 ) ( _ m _l-1 ) aligned If ₁> , then f _ m and f _ a have opposite signs and the nature of lens changes i.e. a convex lens diverges the light rays and concave lens converges the light rays. Thus given option (a) is correct.