Question 511 Mark
What happens when light falls on a mirror?
Answer
View full question & answer→Mirror is silvered on one side, so it does not allow the light to pass through it. It reflects almost whole of the light falling on it.
Questions · Page 2 of 2
[1 Marks Each] QUE - ANS
Question 521 Mark
Define luminous body.
Answer
View full question & answer→The objects which emit light of their own are called luminous bodies, e.g., the sun, the stars, etc.
Question 531 Mark
Close your eyes while looking towards bright sunshine. Now, cover the eyes with your palm still keeping them closed. Do you notice any difference? On the basis of this experience, state whether your eyelids are transparent, translucent or opaque.
Answer
View full question & answer→On the basis of the experience, we observe our eyelids are opaque.
Question 541 Mark
List four natural sources of light.
Answer
View full question & answer→- Sun.
- Stars.
- Fire.
- Jugnu (Firefly).
Question 551 Mark
How can a transparent sheet be converted into a translucent sheet?
Answer
View full question & answer→By greasing the paper with oil or fat.
Question 561 Mark
What change in the path of light takes place when light falls on a shiny surface? What is this called?
Answer
View full question & answer→The light comes back in the same plan when light falls on a shiny surface. This is known as reflection of light.
Question 571 Mark
Name sources of light that are not hot.
Answer
View full question & answer→Tube light, jugnu.
Question 581 Mark
What materials can be used to make a pinhole camera? How can it be used?
Answer
View full question & answer→Pinhole camera can be made with simple material like cardboard, tracing paper etc. It can be used to image the sun and brightly lit objects.
Question 591 Mark
What are the three things required for the formation of shadows?
Answer
View full question & answer→Light, space and opaque object.
Question 601 Mark
What do you mean by scattering of light?
Answer
View full question & answer→When a beam of light falls on a rough surface, it is turned back in different directions, it is called scattering of light.
Question 611 Mark
Why is shadow formed when an opaque object comes in path of light?
Answer
View full question & answer→Light travels in a straight line and when opaque object obstructs it, shadow is formed.
Question 621 Mark
Classify the following into transparent, opaque and translucent objects:
Wax, spectacles, a heap of salt, a stone, dense smoke, wood, skin, balloon, rubber, membrane of a tabla, blood and milk.
Wax, spectacles, a heap of salt, a stone, dense smoke, wood, skin, balloon, rubber, membrane of a tabla, blood and milk.
Answer
View full question & answer→Transparent objects are Spectacles.
Opaque objects are A stone, wood, a heap of salt, dense smoke, and membrane of tabla.
Translucent objects are Blood, milk, wax, skin, balloon, rubber.
Opaque objects are A stone, wood, a heap of salt, dense smoke, and membrane of tabla.
Translucent objects are Blood, milk, wax, skin, balloon, rubber.
Question 631 Mark
What is periscope?
Answer
View full question & answer→Optical object by which we can see objects located above our line of sight.
Question 641 Mark
Define opaque objects with example.
Answer
View full question & answer→Those materials which do not allow light to pass through them, are called opaque objects. Examples wood, stone, etc.
Question 651 Mark
Whether a shadow is two-dimensional or three-dimensional?
Answer
View full question & answer→Shadow is not just the two-dimensional outline that you see on the ground. All the space behind the opaque object up to some distance behind it seems to be filled with the shadow.
