Advertisements
Advertisements
प्रश्न
The following diagram shows the object O and the image I formed by a lens. Copy the diagram and on it mark the positions of the lens LL’ and focus (F). Name the lens.
Advertisements
उत्तर
The complete diagram is shown in the figure in which the position of the lens has been marked by the letter LL’ and the focus as F. The lens is convex (or converging).
संबंधित प्रश्न
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.
What can you see in a completely dark room? If you switch on an electric bulb in this dark room as a light source, explain how you could now see:
(a) the electric bulb
(b) a piece of white paper
Name the physical quantity whose unit is dioptre.
A diverging lens has focal length of 3 cm. Calculate the power.
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
A double convex lens has two surfaces of equal radii R and refractive index \[m = 1 \cdot 5\]
The above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.
The SI unit of the power of a lens is the:
If the lens material and the surrounding liquid have the same refractive index (\[n_2 = n_1\]), then:
