CLASS - 6 || SUBJECT - SCIENCE || Chapter 11 || Light Shadows and Reflection ||

-

 Chapter 11

Light Shadows and Reflection

 

1.   In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?
Ans: No, in a completely dark room no image will be formed because there is no light in the room so no reflection of light takes place and no image will be formed.

2.  Whether the moon is luminous or non-luminous body?
Ans: Moon is non-luminous body.

3.  What is umbra?
Ans: Umbra is the dark region behind object facing light which does not receive light at all.

4.  How does a light ray travel?
Ans: Light ray travels in a straight line.

5.  Give one natural source of light. 
Ans: Sun is a natural source of light.

6.  What is shadow? 
Ans: Shadow is the dark space behind an opaque object where light does not reach.

7.  What is penumbra?
Ans: The less darker shadow formed penumbra.on the periphery of dark shadow is called penumbra.

8.   State difference between a luminous and a non-luminous body.
Ans: The bodies which emit light are called luminous bodies. Example: sun, stars, burning candle etc.
The bodies which does not emit light are called non-luminous bodies. Example: moon, earth, blackboard.

9.  What are the essential conditions for the formation of shadow?
Ans:
(1) There should be an opaque material.
(2) There should be a source of light and screen.
The object must be placed in the path of light. Then shadow is formed on the screen.

10.            Define reflection of light.
Ans: When light rays after striking the smooth and shiny surface return to same medium, this phenomenon is called reflection of light.

11.Explain that light has the property of rectilinear propagation.
Ans: We take three pieces of cardboard. Place them one on the top of one another and make a hole in the middle of each cardboard by using a thick nail. Erect these cards up on the table at a short distance away from each other. Take a candle which is of the same height as the holes in the cards. Light the candle and place it in front of the cards. We see that the light of candle is visible only when the holes on cards lie in a straight line. If we disturb them the light of candle disappears.

Comments

Post a Comment

Popular posts from this blog

CLASS - 3 || SUBJECT - SCIENCE || LESSON – 9 || WATER AS A RESOURCE ||

-
Image
  LESSON – 9 WATER AS A RESOURCE   1.     State of water is interchangeable. How? Water exist in e states, ice, water, and water vapour. All the three states are interchangeable. Ice can be changed into water by melting. Water can be changed into water vapour by evaporation. Water vapour can be brought back to water by condensation. water can also be changed in to ice by freezing.   2.     What is water cycle? Explain it with labelled diagram. The cycle that involves the change of water into water vapour and then into water again in nature is called the water cycle. It is the process by which water circulates between the sky and the earth in a continuous cycle.       ICE Heating     Water heating     Water vapour     Cooling Cooling     3.     What do you mean by purification of water? Impure water is n
Read more

CLASS - 3|| SUBJECT - SCIENCE|| LESSON - 4|| INSECTS||

-
Image
  LESSON – 4 INSECTS   QUESTIONS & ANSWERS :-   1.   What are insects? Name some common insects found in our surroundings. Insects are small creatures that are found almost everywhere. They are different in size, colour and features. Some common insects like ants, bees, butterflies, beetles, mosquitoes, flies, honeybees and grasshoppers can be seen in our surroundings.   2.   What are the main parts of an insect’s body? Draw a labelled diagram of an insect’s body. An insect’s body is divided into three main parts – head, thorax and abdomen. 3.   What do you mean by life cycle? Draw a labelled diagram of the life cycle of a butterfly. Life cycle is the series of changes that happen to a living creature over the course of its lifetime.   4.   Name three insects which are useful to us and how? There are some insects which are very useful to us. a.   Honeybees give us honey and beeswax. Candles, soaps and crayons and made with beeswax. b.   Silkworms giv
Read more

CLASS - 3 || SUBJECT - SCIENCE || LESSON – 10 || SUN AS A RESOURCE ||

-
  LESSON – 10 SUN AS A RESOURCE I.                   DIFFERENTIATE BETWEEN:- 1.     Renewable and non-renewable source of energy Sources of energy that can be used again and again are called renewable source of energy. Natural resources such as coal, petroleum and natural gas form naturally beneath the earth very slowly. The supplies of all these sources are limited and once consumed cannot be made easily again. These are called non-renewable sources of energy.   2.     Solar energy and wind energy. The energy we get from the sun is called solar energy. We get energy from the sun mainly in the form of heat and light. Solar energy captured by solar panels, wind energy is used in windmills to grind gains and generate electricity.     II ANSWER THE FOLLOWING QUESTIONS:-   1.     Why is sun said to be the main source of energy? The sun is the major source of energy on the earth. We get energy from the sun mainly in the form of heat and light. The energy we g
Read more