Science [1 Marks Each] QUE - ANS

Transparent objects I materials : Air, pure water, spectacles lens. Opaque objects / materials : Mirror, pencil, milk, brick. Translucent objects / materials : Tracing paper, muddy water, milky glass, cloud, castor oil.

Natural sources of light: Sun, stars, firefly, fire. Artificial sources of light: Candle, electric bulb, lantern, torch, tubelight.

The person was walking in street light and light was incident on him. Therefore, the thief was able to see the person. The thief was standing on the corner of the lane and was in darkness. Since no light, incident on the thief was the person was not able to see the thief.

Light always travels in a straight line. If an opaque object comes in the path of light rays, they cannot pass through the object and hence a shadow is formed behind the object. Thus, shadow is formed due to the obstruction of the light.

When the light falling on an object gets reflected and enters our eyes we are able to see the objects.

Ground, wall, cloth, paper, buildings or any other opaque surface can be used as a screen.

Solar eclipse and lunar eclipse are astronomical phenomena occurring due to shadow.

Lantern, candle, tubelight are the examples of artificial luminous objects.

Sun, stars and firefly are the examples of natural luminous objects.

The objects that emit their own light are called natural luminous objects.

Objects like the sun that emit light of their own are called luminous objects. (Luminous objects are also known as sources of light.)

Plane mirror

Luminous objects

Straight line

Shadow is formed

Artificial source

Transparent

Sun

No, we cannot see reflection of ourselves in the mirror. In a completely dark room, no light is incident on our body. We see an object when light reflected from It reaches our eyes. Hence, we won’t be able to see a reflection of ourselves in a mirror in a completely dark room.