A thin glass (refractive index 1.5) lens has optical power of $-5\,D$ in air. Its optical power in a liquid medium with refractive index 1.6 will be (1) 1 D (2) $-$1 D (3) 25 D (4) None of these
A thin glass (refractive index 1.5) lens has optical power of $-5\,D$ in air. Its optical power in a liquid medium with refractive index 1.6 will be\\
(1) 1 D\\
(2) $-$1 D\\
(3) 25 D\\
(4) None of these