A thin lens of refractive index `1.5` has focal length of `15 cm` in air. When the lens is placed is a medium of refractive index (4)/(3), its focal length will become …..cm.

A concave mirror and convex lens (both of refractive index 1.5) have focal length 3 cm in air. When they are placed in water ofrefractive index 4/3 , then their new focal lengths will be ......

A thin convex lens of refractive index 1.5cm has 20cm focal length in air. If the lens in completely immersed in a liquid of refractive index. 1.6, then its focal length will be

A thin convex lens of refractive index 1.5cm has 20cm focal length in air. If the lens in completely immersed in a liquid of refractive index. 1.6, then its focal length will be

A biconvex lens of refractive index "1.5" has a focal length of "20cm" in air.Its focal length when immersed in a liquid of refractive index "1.6" will be:

The focal length of lens of refractive index 1.5 in air is 30 cm When it is immersed in water of refractive index (4)/(3) ,then its focal length will be

The focal length of lens of refractive index 1.5 in air is 30cm When it is immersed in water of refractive index (4)/(3) ,then its focal length will be

A convex lens of refractive index 1.5 has a focal length of 18 cm in air. Calculate the change in its focal length when it is immersed in water of refractive index (4)/(3) .

A thin lens made of glass of refractive index mu = 1.5 has a focal length equal to 12 cm in air. It is now immersed in water ( mu=4/3 ). Its new focal length is