Exercise

When the lights of a brightly lit room are suddenly put out, the people of the room are blinded for a moment. Why?

What is the advantage of binocular vision? What does persistence of vision mean?

Which eyepiece called negative eyepiece?

What are short-sight and long-sight? What are the reasons for these defects? How can they be remedied?

The focal length of simple microscope is $20 \mathrm{cm}$. Magnifying power of microscope when image is formed at near point $\left(\mathrm{D}=25 \mathrm{cm}\right)$.

How does a microscope eyepiece work?

A compound microscope consists of two convex lenses having a focal length of $1.5 \mathrm{cm}$ and $5 \mathrm{cm}$. When an object is kept at a distance of $1.6 \mathrm{cm}$ from the objective, the final image is virtual and lies at a distance of $25 \mathrm{cm}$ from the eyepiece. Calculate magnifying power of the compound microscope in this setup.

Draw a labelled ray diagram of an image formed by a refracting telescope with final image formed at infinity Derive an expression for its magnifying power with the final image at infinity.