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 Image-Distance

u (cm) v (cm)

1. -60 +12

2. -30 +15

3. -20 +20

4. -15 +30

5. -12 +60

6. -9 +90

i. The focal length of convex lens is [ ]

a) 5 cm b) 10 cm c) 15 cm d) 20 cm​

Answer 1

Answer:

my answer is 1.72

2.45

3.40

4.45

5.72

6.99