Question

A student focused the image of a candle flame on a white screen by placing the flame at

various distance from a convex lens. He noted his observation as:

S. No. Distance of the flame from the lens

(in cm)

Distance of the screen from the lens

(in cm)

1. -60 +20

2. -40 +24

3. -30 +30

4. -24 +40

5. -12 +70

(i) What is the focal length of convex lens used by the student.
Magnification of the convex lens on the basis of first observation is

(a) – 1/2 (b) – 1/3 (c) – 4 (d) – 2​

Answer 1

Answer:

refer the picture for answer