Question 1

Which of the following is a luminous object?

Accepted Answer

A luminous object is one that emits its own light. Among the given options, the Sun is a natural source of light and produces its own light, whereas the moon, a wooden chair, and a pencil do not emit their own light and are non-luminous objects.

Question 2

Which of the following materials is opaque?

Accepted Answer

Opaque materials are those through which we cannot see at all, as they do not allow light to pass through them. A wooden board is an opaque object, whereas air, water, and a glass sheet are transparent or translucent.

Question 3

Which of the following is a transparent medium?

Accepted Answer

Transparent materials allow light to pass through them completely, enabling us to see clearly through them. Clean water is transparent, while butter paper is translucent and wood and brick are opaque.

Question 4

What is formed when an opaque object comes in the path of light?

Accepted Answer

When an opaque object blocks the path of light, it creates a dark patch behind it, which is known as a shadow. Light travels in a straight line, and when it is obstructed, a shadow is formed.

Question 5

Which of the following objects is translucent?

Accepted Answer

Translucent objects allow only a fraction of light to pass through them, making objects on the other side look hazy or unclear. Oiled paper is a classic example of a translucent material.

Light, Shadows and Reflections