Rajesh Singh, Indu Gupta and, Sikha Sharma Solutions for Chapter: Light – Reflection and Refraction, Exercise 3: Long Answer Type Questions

Draw ray diagram 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 side of the lens. If the image is three times the size of the flame and the distance between lens and image is $80 \mathrm{c} \mathrm{m},$ at what distance should the candle be placed from the lens? What is the nature of the image at a distance of $80 \mathrm{c} \mathrm{m}$ and 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 $\frac{1}{3}\mathrm{rd}$ to 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?

Note: To make the question academically more meaningful use lens in the last sentence instead of the word length.

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?

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 as said above.