IMPORTANT QUESTIONS

A small candle, $1.5 \mathrm{cm}$ in size is placed at $15 \mathrm{cm}$ in front of a concave mirror of radius of curvature $20.0 \mathrm{cm}$. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Describe the nature and size of the image. 

A $1.8 \mathrm{cm}$ needle is placed $16 \mathrm{cm}$ away from a convex mirror of focal length $20 \mathrm{cm}$. Give the location of the image and the magnification. 

An object $0.2 \mathrm{m}$ high is placed at a distance of $0.4 \mathrm{m}$ from a concave mirror of radius of curvature $0.3 \mathrm{m}$. Find the position, nature, and size of the image formed. 

A concave lens has a focal length of $20 \mathrm{cm}$. At what distance should an object from the lens be placed so that it forms an image at $15 \mathrm{cm}$ from the lens? Also, find the magnification of the lens.

A convex lens has a focal length of $20 \mathrm{cm}$. Calculate at what distance should the object be placed from the lens so that it forms an image at $40 \mathrm{cm}$ on the other side of the lens. Find the magnification produced by the lens in this case. 

A concave lens has focal length $30 \mathrm{cm}$. At what distance from the lens a $4 \mathrm{cm}$ tall object be placed so that it forms an image at $20 \mathrm{cm}$ from the lens? Also calculate the size of the image formed. 
 

Calculate the distance at which an object should be placed in front of convex lens of focal length $15 \mathrm{cm}$ to obtain an image triple of its size? 

A diverging lens of focal length $20 \mathrm{cm}$ forms an image of $12 \mathrm{cm}$ from the lens. Draw a scale diagram for the formation of image.