A thin glass (refractive index 1 . 5 ) lens has an optical power of - 5 D in the air. Its optical power in a liquid medium with refractive index 1 . 6 will be

Step-by-step solution

1 f a = ( μ - 1 ) ( 1 R 1 - 1 R 2 ) = 1.5 - 1 1 R 1 - 1 R 2                 … … … … . . i a n d 1 f m = μ g - μ m μ m ( 1 R 1 - 1 R 2 ) 1 f m = 1.5 1.6 - 1 1 R 1 - 1 R 2         … … … . . i i Thus, f m f a = 1.5 - 1 1.5 1.6 - 1 = - 8 f m =   - 8 × f ₐ = - 8 × - 1 5                   ∵ f a = 1 p = - 1 5 m = 1.6   m &#875