Convex side of a plano-convex lens is fully immersed in a liquid, of same refractive index (equal to 8/5) as that of the lens. Which one among the following is correct regarding the image of a point source of light placed in air at 40 cm away from the lens? (Assume the focal length of the plano-convex lens as 20 cm)

A convex lens has a focal length of 15 cm. At what distance should an object be placed in front of the lens to get a real image of the same size of the object?

A luminous object is placed at a distance of 40 cm from a converging lens of focal length 25 cm. The image obtained in the screen is

A point object is placed at the centre of curvature of a spherical concave mirror. Which one among the following would be the correct location of image formed ?

Which one among the following is the correct focal length of a combination of lenses of power 2.5 D and -2.0 D ?

Which one of the following statements is correct regarding the travel of a light beam from a rare to a dense medium?