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प्रश्न
A student wants to project the image of a candle flame on the walls of school laboratory by using a lens:-
(a) Which type of lens should be use and why?
(b) At what distance in terms of focal length 'F' of the lens should be place the candle flame so as to get (i) a magnified, and (ii) a diminished image respectively on the wall?
(c) Draw ray diagram to show the formation of the image in each case?
उत्तर
(a) He should use a convex lens as it forms real images.
(b) He should place the candle flame between F and 2F (the focus and centre of curvature of the lens) to get the magnified image on the wall while the diminished image is obtained when the object is located at a distance greater than 2F.
(c) The ray diagram for the formation of the magnified image is shown below:
The ray diagram for the formation of the diminished image is shown below:
संबंधित प्रश्न
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).
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
Fill in the following blank with suitable word:
The image in a convex lens depends upon the distance of the ........... from the lens.
Three convex lenses are available having focal lengths of 4 cm, 40 cm and 4 m respectively. Which one would you choose as a magnifying glass and why?
A convex lens produces an inverted image magnified three times of an object placed at a distance of 15 cm from it. Calculate focal length of the lens.
Which of the above two cases illustrates the working of a magnifying glass?
A convex lens of focal length 15 cm produces a magnification of +4. The object is placed:
(a) at a distance of 15 cm
(b) between 15 cm and 30 cm
(c) at less than 15 cm
(d) beyond 30 cm
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.
A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. The positions suggested by the students were as
A. 12.7 cm
B. 29.7 cm
C. 57.7 cm
D. 72.7 cm
The correct position of the screen was suggested by
(a) A
(b) B
(c) C
(d) D
List four properties of the image formed by a convex mirror.
