Narendra Kumar Solutions for Chapter: Light - Reflection and Refraction, Exercise 2: Test Your Self Exercise 1

A student determines the focal length of a device X, by focussing the image of a far off an object on the screen positioned as shown in the figure below. 
What is the focal length of the device X?

Rays from sun converge at a point $10 \mathrm{cm}$ in front of a concave mirror. Where should be an object placed so that size of its image is equal to the size of the object? 

State the law of reflection.

Define the focus of the concave mirror.

Why a convex mirror is used as the rear-view mirror of a vehicle and not a plane mirror? 

How far an object should be placed from the pole of a concave mirror of focal length $20 \mathrm{cm}$ to do a real image whose size is $1/5$ the size of the object? 

A concave mirror produces three times enlarged image of an object placed at a distance $15 \mathrm{cm}$ in front of it. Calculate the radius of curvature of the mirror.