Lakhmir Singh and Manjit Kaur Solutions for Chapter: Refraction of Light, Exercise 18: Long Answer Type Questions

State one practical application each of the use of a lens of focal length $8 \mathrm{cm}$ with the object in position $12 \mathrm{cm}$ and $6 \mathrm{cm}$.

An object $3 \mathrm{cm}$ high is placed $24 \mathrm{cm}$ away from a convex lens of focal length $8 \mathrm{cm}$. Find by calculations, the position, height and nature of the image.

If the object $3 \mathrm{cm}$ high is moved to a point only $3 \mathrm{cm}$ away from the lens of focal length $8 \mathrm{cm}$, what is the new position, height and nature of the image?

(i) An object $3 \mathrm{cm}$ high is placed $24 \mathrm{cm}$ away from a convex lens of focal length $8 \mathrm{cm}$. 

(ii) If the object $3 \mathrm{cm}$ high is moved to a point only $3 \mathrm{cm}$ away from the lens of focal length $8 \mathrm{cm}$.

Which of the two cases illustrates the working of a magnifying glass?

Find the nature, position and magnification of the images formed by a convex lens of focal length $0.20 \mathrm{m}$ if the object is placed at a distance of $0.50 \mathrm{m}$.

Find the nature, position and magnification of the images formed by a convex lens of focal length $0.20 \mathrm{m}$ if the object is placed at a distance of $0.25 \mathrm{m}$.

Find the nature, position and magnification of the images formed by a convex lens of focal length $0.20 \mathrm{m}$ if the object is placed at a distance of: $0.15 \mathrm{m}$

Which of the cases: object placed at a distance of,  $0.50 \mathrm{m}, 0.25 \mathrm{m} \mathrm{and} 0.15 \mathrm{m}$ represents the use of convex lens of focal length $0.20 \mathrm{m}$ in a film projector, in a camera and as a magnifying glass?