Advertisements
Advertisements
Question
Answer the following question.
List four precautions which a student should observe while determining the focal length of a given convex lens by obtaining an image of a distant object on a screen.
Solution
Following are the precautions while making the image by the help of convex lens:
1) Fix the convex lens vertically in the lens holder.
2) The base of the lens and white screen should be in a line with the measuring scale.
3) Record the position of the lens and screen only when a well-defined sharp image is formed.
4) There should not be an obstacle in the path of the convex lens.
APPEARS IN
RELATED QUESTIONS
An object 5 cm is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position, nature and size of the image.
Write one condition where it does not bend when entering a medium of different optical density.
Where should an object be placed in front of a convex lens so as to obtain its real, inverted and magnified image?
Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).
An object is placed at a distance equal to 2f in front of a convex lens. Draw a labelled ray diagram to show the formation of image. State two characteristics of the image formed.
What kind of lens can form:
an inverted magnified image?
A convex lens is placed in water. Its focal length will ______.
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
Distinguish between:
Concave lens and Convex lens
Observe the following figure and complete the table:
| Points | Answer |
| (i) Position of the object | |
| (ii) Position of the image | |
| (iii) Size of the image | |
| (iv) Nature of the image |
