A point source of light is placed inside water and a thin converging lens of focal length f is placed just outside the surface of water. The image of source is formed at a distance of 50 cm from the surface of water. When the lens is placed just inside the water surface the image is formed at a distance of 40 cm from the surface of water. if focal length of the lens in air is f=(100k)/8 cm, then find the value of k. (given refractive index of lens is 3/2 and that of water is 4/3 and in both cases image is formed inside water for the viewer in air).

A point source of light is placed inside water and a thin converging l

1.	A point source of light is placed inside water and a thin converging lens of focal length f is placed just outside the surface of water. The image of source is formed at a distance of 50 cm from the surface of water. When the lens is placed just inside the water surface the image is formed at a distance of 40 cm from the surface of water. if focal length of the lens in air is f=(100k)/8 cm, then find the value of k. (given refractive index of lens is 3/2 and that of water is 4/3 and in both cases image is formed inside water for the viewer in air).
Answer» ANSWER :4