Question

Analyse the following observation table showing variation of image distance (v) with

object distance (u) in case of a convex lens and answer the questions that follow, without

doing any calculations:

S.No Object distance u (cm) Image distance v (cm)

1 -90 +18

2 -60 +20

3 -30 +30

4 -20 +60

5 -18 +90

6 -10 +100

i) What is the focal length of the convex lens?

a) -10 b) +10 c) -15 d) +15

ii) Write the serial number of that observation which is not correct.

a) S.No. 1 b) S.No. 4 c) S.No. 3 d) S.No. 6

iii) The approximate value of magnification in case of S.No. 4

a) -2 b) -3 c) +3 d) +2

iv) The image formed in case of S.No. 2 is

a) Virtual & Enlarged b) Virtual & Diminished

c) Real & Diminished d) Real & Enlarged

v) If a convex lens is used to focus sunlight on a paper, where the paper should be

placed so that it catches fire.

a) At centre of curvature b) At principal focus

c) At optical centre of lens
d) At 25 cm away​

Answer 1

Answer:

well, I can't give you tje accurate information but it's 3rd option i think so