3 stationary wave 4 none of the above A screen is placed 90

Last updated: 6/6/2023

3 stationary wave 4 none of the above A screen is placed 90 cm from an object The image of an object on the screen is formed by a convex lens at two different locations separated by 20 cm The focal length of the lens is 1 18 cm 2 21 4 cm 3 60 cm 4 85 6 cm