Advertisements
Advertisements
प्रश्न
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
उत्तर
Parallel rays of light are refracted by a convex lens to a point called the focus.
APPEARS IN
संबंधित प्रश्न
Draw a labelled ray diagram to show how a ray of light is refracted when it passes:
from air into an optically denser medium.
Where should an object be placed in front of a convex lens so as to obtain its virtual, erect and magnified image?
Define principal axis, principal focus and focal length of a convex lens.
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
What is the focal length of this lens?
A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm. The focal length of this combination of lenses will be:
(a) +10 cm
(b) +20 cm
(c) −10 cm
(d) −20 cm
The focal length of a thin convex lens is ______ than that of a thick convex lens.
Study the diagram given below.
- Name the lens LL’.
- What are the points O and O’ called?
- Complete the diagram to form the image of the object AB.
- State the three characteristics of the image.
- Name a device in which this action of lens is used.
An object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find (i) the position (ii) the magnification and (iii) the nature of the image formed.
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).
Distinguish between:
Concave lens and Convex lens
