Advertisements
Advertisements
प्रश्न
A convex lens has a divergent action and a concave lens has a convergent action.
विकल्प
True
False
उत्तर
This statement is False.
Explanation:
Convex lenses have a convergent action, not a divergent action. They converge parallel incident rays of light to a focal point after refraction, hence they are often called converging lenses.
Concave lenses, on the other hand, have a divergent action. They diverge parallel incident rays of light as if they are coming from a virtual focus point hence they are often called diverging lenses.
APPEARS IN
संबंधित प्रश्न
A student is using a convex lens of focal length 18 cm to study the image formation by it for the various positions of the object. He observes that when he places the object at 27 cm, the location of the image is at 54 cm on the other side of the lens. Identify from the following diagram the three rays that are obeying the laws of refraction and may be used to draw the corresponding ray diagram.
(A) 1, 2 and 4
(B) 1, 3 and 5
(C) 2, 4 and 5
(D) 2, 3 and 4
A student focuses the image of a well-illuminated distant object on a screen using a convex lens. After that, he gradually moves the object towards the lens and each time focuses its image on the screen by adjusting the lens.
(i) In which direction, towards the screen or away from the screen, does he move the lens?
(ii) What happens to the size of the image? Does it decrease or increase?
(iii) What happens to the image on the screen when he moves the object very close to the lens?
A beam of light travelling in air is incident of water. Draw a ray-diagram indicating the change in its path in water.
Draw a labelled ray diagram to show how a ray of light passes through a parallel sided glass block:
if it hits the glass block at an angle other than 90° (that is, obliquely to the glass block).
A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below:
Which of the following could be inside the box?
(a) a rectangular glass block
(b) a concave lens
(c) a convex lens
(d) a glass prism
What would be the diameter of the image of the flower on the film?
Why do we say that the ‘2F’ and ‘F’ points of a convex lens can be regarded as a sort of ‘turning points’ as far as the nature of the image formed by it is concerned?
Which of the following statements is true?
The above image shows a thin lens with a focal length of 5m.
- What is the kind of lens shown in the above figure?
- If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed.
- Draw a neatly labelled diagram of the image formation mentioned in (ii).
