The eyes of a person are focused

1. On a nearby object, and
2. On a distant object, turn by turn. In which case:

1. The focal length of ye-lens will be the maximum?
2. The converging power of eye-lens will be the maximum?

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

Five persons A, B, C, D and E have diabetes, leukaemia, asthma, meningitis and hepatitis, respectively.

1. Which of these persons can donate eyes?
2. Which of these persons cannot donate eyes?

How could you show that the colours of the spectrum combine to give white light?

Why does it take some time to see objects in a dim room when you enter the room from bright
sunshine outside?

Draw a diagram to show the refraction of light through a glass prism. On this diagram, mark:

1. Incident ray.
2. Emergent ray, and.
3. Angle of deviation.

Why do stars seem higher than they actually are? Illustrate your answer with the help of a diagram.

State the role of ciliary muscles in accommodation.

How does the convex eye-lens differ from the ordinary convex lens made of glass?

A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?