Question

Q1. What do you mean by power of a lens? What is its S.l. unit?
Find the power of a lens whose focal length is 25 cm.
OR
An object 5cm in length is held 25cm away from a converging
lens of focal length 10cm. Draw the ray diagram and iind
the position, size and the nature of the image formed.
OR
What is atmospheric refraction? Why do stars twinkle at
night?
Short answer type questions (3x3/2=1072) marks
Q2. State and explain Ohm's law.
OR
What do you mean by an electric current? What is its S.I.
unit? Name the instrument which is used to measure
electric current?​

Answer 1

Answer:

reciprocal of focal length in meters is known as power of a lense .diopter is its sI unit.