A slide measuring 24 mm in height is to be projected onto a vertical screen that is…
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A slide measuring 24 mm in height is to be projected onto a vertical screen that is 2.4 m high. The screen is fixed 8.0 m away from the projecting lens. The film slide is placed on the principal axis of the lens and the image is required to just fill the screen.
(i) Calculate the linear magnification needed to obtain the required image size.
(ii) Determine the distance of the slide from the lens for this setting.
(iii) Find the focal length of the projecting lens.
(iv) If the screen is shifted 0.50 m further away from the lens, by how much should the lens be moved (towards or away from the slide) to regain a sharp focus on the screen? (Assume the slide and lens remain coaxial.)