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प्रश्न
The power of a lens is negative. State whether it is convex or concave.
उत्तर
It is a concave.
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संबंधित प्रश्न
If the numerical value of the power of this lens is 10 D, what is its focal length in the Cartesian system ?
Draw a diagram to show how a converging lens focusses parallel rays of light?
Which type of lens is
a diverging lens? Explain your answer with diagrams.
With the help of a diagram, explain why the image of an object viewed through a concave lens appears smaller and closer than the object.
When a fork is seen through lenses A and B one by one, it appears as shown in the diagrams. What is the nature of (i) lens A, and (ii) lens B? Give reason for your answer.
A concave lens of 20 cm focal length forms an image 15 cm from the lens. Compute the object distance.
The power of a concave lens is 10 D and that of a convex lens is 6 D. When these two lenses are placed in contact with each other, the power of their combination will be :
(a) +16 D
(b) +4 D
(c) −16 D
(d) −4 D
The power of a converging lens is 4.5 D and that of a diverging lens is 3 D. The power of this combination of lenses placed close together is :
(a) +1.5D
(b) +7.5D
(c) −7.5D
(d) −1.5D
An object is placed in front of a lens between its optical centre and focus. The formed image is virtual, erect, and diminished. Name the lens used.
Convex magnifying glass is called divergent magnifying glass and concave magnifying glass is called converging magnifying glass.
