While doing experiments with candle to find focal length of a concave mirror, the candle is placed

A full length image of a distant tall building can definitely be seen by using

The centre of the sphere of which the spherical mirror forms a part is called

What is the value of $\theta$ in the following diagram?

If an object is placed between focus and optical centre of convex lens, image formed is__

Which of the following lenses would you prefer to use while reading small letters found in a dictionary__