5. In an experiment to determine the focal length of a convex lens, the image of a distant tree is
obtained on the screen. To determine the focal length of the lens, you are required to measure the
distance between the :-
(a) Lens and the tree only
(b) Lens and the screen only
(c) Screen and the tree only
(d) Screen and the tree and also between the screen and the lens
Answers
Explanation:
Fix the convex lens on the lens holder or stand and place it place it on the table near an open window of the laboratory.
2. Locate a distant tree/building from the open glass window (if an open window is not available then obtain the image of the window itself on the screen.
3. Place the screen behind the convex lens.
4. Adjust the position of the convex lens and the screen so that a sharp, inverted and diminished image of a distant object is formed clearly on the screen.
5. Note the positions of the screen and the convex lens stand with the help of measuring scale.
6. Find the distance between the optical centre of the lens and the screen. This distance is equal to the focal length of the convex lens. Record the the focal length.
7. Repeat the experiment a few times by changing the positions of the convex lens stand and note the corresponding changed position of the screen.
8. Calculate the mean value of the focal length.
hope it helps u
Answer:
b, lens and screen only
if the object is at infinity, the image will form at focus.