NEETPhysicsGeometrical OpticsMCQ+4 / −1
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. If a parallel beam of light falling on 'A' leaves 'B' as a parallel beam, then the distance 'd' in cm will be :
- A30
- B25
- C15
- D50
View written solutionFree
Correct answer: C

Parallel beam of light after refraction from convex lens converge at the focus of convex lens. In question it is given light after refraction pass through concave lens becomes parallel. Therefore light refracted from convex lens virtually meet at focus of concave lens.
According to above ray diagram, d = fA $-$ fB
= 20 $-$ 5
= 15 cm
More from Geometrical Optics
- A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since :2021 · MCQ
- A point object is placed at a distance of 60 cm from a convex lens of focal length 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a… Includes diagram2021 · MCQ
- A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism A) and emerges normally from the opposite surface. If the refractive index of the material of the prism is , then the angle of…2020 · MCQ
- The Brewster's angle ib for an interface should be :2020 · MCQ
- In total internal reflection when the angle of incidence is equal to the critical angle for the pair of media in contact, what will be angle of refraction?2019 · MCQ
- Pick the wrong answer in the context with rainbow.2019 · MCQ
- Two similar thin equi-convex lenses, of focal length f each, are kept coaxially in contact with each other such that the focal length of the combination is F1. When the space between the two lenses is filled with glycerin (which has the…2019 · MCQ
- An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be2018 · MCQ