Narendra Kumar Solutions for Chapter: Light - Reflection and Refraction, Exercise 7: NCERT EXEMPLAR PROBLEMS

Draw ray diagrams showing the image formation by a convex mirror when an object is placed at finite distance from the mirror.

The image of a candle flame formed by a lens is obtained on a screen placed on the other side of the lens. If the image is three times the size of the flame and the distance between lens and image is $80 \mathrm{cm}$, at what distance should the candle be placed from the lens? What is the nature of the image at a distance of $80 \mathrm{cm}$ from the lens?

Size of image of an object by a mirror having a focal length of $20 \mathrm{cm}$ is observed to be reduced to $\frac{1}{3}$rd of its size. At what distance the object has been placed from the mirror? What is the nature of the image and the mirror?

Define power of a lens. What is its unit? One student uses a lens of focal length $50 \mathrm{cm}$ and another of $-50 \mathrm{cm}$. What is the nature of the lens and its power used by each of them?

A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under

Position of Candle $=12.0 \mathrm{cm}$

Position of convex lens $=50.0 \mathrm{cm}$

Position of the screen $=88.0 \mathrm{cm}$

What is the focal length of the convex lens?

A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under

Position of Candle $=12.0 \mathrm{cm}$

Position of convex lens $=50.0 \mathrm{cm}$

Position of the screen $=88.0 \mathrm{cm}$

Where will the image be formed if he shifts the candle towards the lens at a position of $31.0 \mathrm{cm}$?

A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under

Position of Candle $=12.0 \mathrm{cm}$

Position of convex lens $=50.0 \mathrm{cm}$

Position of the screen $=88.0 \mathrm{cm}$

What will be the nature of the image formed if he further shifts the candle towards the lens from position $31.0 \mathrm{cm}$.

 A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under:

Position of Candle $=12.0 \mathrm{cm}$

Position of convex lens $=50.0 \mathrm{cm}$

Position of the screen $=88.0 \mathrm{cm}$

Draw a ray diagram to show the formation of the image in case if he further shifts the candle towards the lens from position $31.0 \mathrm{cm}$.