Advertisements
Advertisements
प्रश्न
A small bulb is placed at the focal point of a converging lens. When the bulb is switched on, the lens produces:
(a) a convergent beam of light
(b) a divergent beam of light
(c) a parallel beam of light
(d) a patch of coloured light
उत्तर
A parallel beam of light
The reason being, a beam of light coming from the focus of a converging lens becomes parallel, after refraction from the lens.
APPEARS IN
संबंधित प्रश्न
Copy and complete the diagram below to show what happens to the rays of light when they pass through the concave lens:
An object lies at a distance of 2f from a concave lens of focal length f. Draw a ray-diagram to illustrate the image formation.
Give the position, size and nature of image of formed by a concave lens when the object is placed:
at infinity.
State whether the following statement is true or false:
Short-sightedness can be cured by using a concave lens.
A person finds difficulty in seeing nearby objects clearly. His vision can be corrected by using spectacles containing:
(a) converging lenses
(b) diverging lenses
(c) prismatic lenses
(d) chromatic lenses
Out of the two lenses, one concave and the other convex, state which one will show the divergent action on a light beam. Draw diagrams to illustrate your answer.
At what distance from a concave lens of focal length 20 cm a 6 cm tall object be placed so as to obtain its image at 15 cm from the lens? Also calculate the size of the image formed.
Draw a ray diagram to justify your answer for the above situation and label it.
State three characteristics of the image of an extended source, formed by a concave lens.
Copy the following figure and complete it to show the formation of the image of the object AB. Name the lens used in the figure.
