Name the atmospheric phenomenon due to which the sun can be seen above the horizon about two minutes before actual sunrise.

Explain why, we cannot see our seats first when we enter a darkened cinema hall from bright light but gradually they become visible.

Suggest how your irises help to protect the retinas of your eyes from damage by bright light.

What are rods and cones in the retina of an? Why is our night vision relatively poor compared to the night vision of an owl?

The power of a lens is +1.5D. Name the type of defects vision that can be corrected by using this lens. Find the focal length of the lens.

Why does the Sun appear reddish early in the morning?

When we look nearby objects, what happens to the focal length of our eye?

Describe how you could demonstrate that white light is composed of a number of colours.

What are the two most common defects of vision (or defects of eye)? How are they corrected?

Define the term power of accommodation. Write the modification in the curvature of the eye lens which enables us to see the nearby objects clearly?