Light, Shadows, and Reflections | Science 6th | Chapter 11 | Questions and Answers

JANDKNCERT | Science 6^th |

Light, Shadows, and Reflections | Science 6th | Chapter 11 | Questions and Answers

 

Chapter 11: Light, Shadows, and Reflections

Dear Students, in Chapter 10, you learnt about the Motion and the Measurement of Distances, in which you learnt about Rectilinear Motion, Circular Motion, Periodic Motion, and also how to measure distances using a unit system.

In this chapter, you will learn the following points:

·        Opaque objects do not allow light to pass through them.

·        Transparent objects allow light to pass through them and we can see through these objects.

·        Translucent objects allow light to pass through them partially.

·     Shadows are formed when an opaque object comes in the path of light.

·        A pinhole camera can be made with simple materials and can be used to image the Sun and brightly lit objects.

·        Mirror reflection gives us clear images.

·        Images are very different from shadows.

·        Light travels in a straight line.

 

Let us try to answer some questions taken from the NCERT Book of Science Class 6th. This Exercise is taken from the same book.

 

Exercises

 

Q1. Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

OWS

AKE

OPAQ

UEO

BJEC

TSM

SHAD

 

Ans.

 

 

OPAQ

UEO

BJEC

TSM

AKE

SHAD

OWS

 

 

 

(OPAQUE OBJECTS MAKE SHADOWS)

Q2. Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:

Air, water, a piece of rock, a sheet of aluminium, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.

Ans.

Object Name	Opaque, Transparent, or Translucent	Luminous or No-luminous
Air	Transparent	Non-luminous
Water	Transparent	Non-luminous
A piece of rock	Opaque	Non-luminous
A sheet of aluminium	Opaque	Non-luminous
A mirror	Opaque	Non-luminous
A wooden board	Opaque	Non-luminous
A sheet of polythene	Translucent	Non-luminous
A CD	Translucent	Non-luminous
A smoke	Translucent	Non-luminous
A sheet of plain glass	Transparent	Non-luminous
Fog	Translucent	Non-luminous
A piece of red hot iron	Opaque	Luminous
An umbrella	Opaque	Non-luminous
A lighted fluorescent tube	Opaque	Luminous
A wall	Opaque	Non-luminous
A sheet of carbon paper	Opaque	Non-luminous
The flame of a gas burner	Translucent	Luminous
A sheet of cardboard	Opaque	Non-luminous
A lighted torch	Opaque	Luminous
A sheet of cellophane	Translucent	Non-luminous
A wire mesh	Translucent	Non-luminous
Kerosene stove	Opaque	Luminous
Sun	Opaque	Luminous
Firefly	Opaque	Luminous
Moon	Opaque	Non-luminous

 

Q3. Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

Ans. Yes, if a cylindrical object is held horizontally against the light it gives a circular shadow, and if the same object is held vertically it creates a rectangular shadow.

Q4. 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. Reflection takes place in presence of sunlight. One cannot see the reflection of himself if there is no light in the room. So, in a completely dark room, we cannot see our reflection in the mirror.