Question

a) State laws of refraction
b) Define refractive index of the medium. (3)

3. An object 4 cm high is placed at a distance of 10cm from a convex lens of
focal length 20cm. Find the position, nature and size of the image. (3)

4. a) Define power of a lens.
b) A lens used in spectacles has power +2.0D. What is the focal length of the
lens ? Is the lens a converging or diverging ? (3)

5. Why stars are twinkling but planets do not ? (3)​

Answer 1

Answer:

points Aur badhao answer mil jayega...

I promise.....

Answer 2

Answer:

Third law of motion is Newton