A parallel beam of monochromatic light falls on a combination of a convex lens and a concave lens of focal lengths 15 cm and 5 cm respectively. What is the distance between the two lenses to obtain a parallel beam of light from the concave lens ?

Which of the two diverges a beam of parallel rays of light : convex lens or concave lens ?

A parallel beam of white light fall on a combination of a concave and a convex lens, both of the same meterial. Their focal lengths are 15 cm and 30 cm respectively for the mean wavelength in white light. On the other side of the lens system, one sees coloured patterns with violet colour at the outer edge.

A parallel beam of white light falls on a combination of a concave and a convex lens, both of the same material. Their foacl lengths are 15cm and 30cm, respectively for the mean wavelength in white light. On the other side of the lens system, one sees colored patterns with violet color at the outer edge.

A parallel beam of white light falls on a combination of a concave and a convex lens, both of the same material. Their foacl lengths are 15cm and 30cm, respectively for the mean wavelength in white light. On the other side of the lens system, one sees colored patterns with violet color at the outer edge.

A convex lens A of focal length 20cm and a concave lens B of focal length 10 cm are kept along the same axis with a distance d between them. If a parallel beam, then d is

A convex lens A of focal length 20cm and a concave lens B of focal length 10 cm are kept along the same axis with a distance d between them. If a parallel beam, then d is

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distance d between them. What is the value of d if a parallel beam of light incident on A leaves B as a parallel beam ?

A convex lens A of focal length 20cm and a concave lens G of focal length 5cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance d in cm will be