Advertisements
Advertisements
प्रश्न
A convex lens is of focal length 20 cm. Find its power.
What is the power of a convex lens of focal length 20 cm?
Advertisements
उत्तर
Given: Focal length f = 20 cm = 0.2 m
Power = `1/"Focal length in m"`
= `1/0.2`
= 5D
APPEARS IN
संबंधित प्रश्न
Define the power of a lens.
Ranbir claims to have obtained an image twice the size of the object with a concave lens. Is he correct? Give a reason for your answer.
A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens
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 unit of power of a lens? Define the unit of power of a lens.
How does focal length of a lens change when red light incident on it is replaced by violet light? Give reason for your answer.
A lens forms an upright and diminished image of an object, irrespective of its position. What kind of lens is this? Draw an outline ray diagram to show the formation of the image. State the position and one more characteristic of the image.
Complete the diagram to show the formation of the image of the object AB.
(i) Name the Lens LL’.
(ii) Where is the image of the object AB formed?
(iii) State three characteristics of the image.
The power of the magnifying glass depends on the distance of the magnifying glass from object.
For a lens immersed in a medium of refractive index \[n_1\], the power is related to the focal length by:
