Advertisements
Advertisements
प्रश्न
A student obtained clear image of window grills on the screen. But the teacher told him to get the image of a tree far away, instead of window. To get a clear image, the lens must be ............................
पर्याय
moved towards the screen.
moved away from the screen.
moved behind the screen.
moved far away from the screen.
उत्तर
moved towards the screen.
APPEARS IN
संबंधित प्रश्न
Define the principal focus of a concave lens.
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
If the image formed by a lens is always diminished and erect, what is the nature of the lens?
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.
An object is placed 10 cm from a lens of focal length 5 cm. Draw the ray diagrams to show the formation of image if the lens is diverging.
Construct ray diagrams to illustrate the formation of a virtual image using a converging lens,
Construct ray diagrams to illustrate the formation of a virtual image using a diverging lens.
When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at he focus of:
(a) either a convex mirror or convex lens
(b) either a concave mirror or concave lens
(c) either a concave mirror or convex lens
(d) either a convex mirror or concave lens
Name one of the common defects of vision and the type of lens used to remove it.
What type of lens is used to correct
myopia?
State whether the following statement is true or false:
Short-sightedness can be cured by using a concave lens.
Complete the following sentence:
A short-sighted person cannot see ............ objects clearly. Short-sightedness can be corrected by using ........... lenses.
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
How will you differentiate between a convex and a concave lens by looking at
- a distant object,
- a printed page?
The diagrams showing the correct path of the ray after passing through the lens are:
 |
 |
| I | II |
 |
 |
| III | IV |
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.
Draw images in case of a concave lens when the object is at infinity.
Convex lens : converging : : concave lens : _______
If the power of a lens is -4.0 D, then it means that the lens is a ______.
