Science NCERT Grade 6, Chapter 11, Light, Shadows and Reflections as the name suggests, talks about the basics of light and its associated concepts. The chapter begins with an explanation of luminous and non-luminous objects which is explained along with examples. The first section of the chapter- Light, Shadows and Reflections differentiates between transparent, opaque and translucent objects and defines each term along with suitable examples, activities and images. The next section of the chapter, Light, Shadows and Reflections talks about shadows and its characteristics with the help of suitable activities.
The section concludes by stating that shadows can only be obtained on a screen. The third section of the chapter, Light, Shadows and Reflections demonstrates the construction and working of a pinhole camera which is supplemented with associated images. The last section of the chapter, Light, Shadows and Reflections explains the concept of mirrors and reflections with the help of activities whose conclusion proves that light reflects a beam of light.

The chapter, Light, Shadows and Reflections covers the following topics -

  1. Transparent, Opaque and Translucent Objects
  2. What Exactly are Shadows?
  3. A Pinhole Camera
  4. Mirrors and Reflections

Page No 113:

Question 1:

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

Answer:

Opaque objects make shadows.



Page No 114:

Question 2:

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.

Answer:

Object
Object is Transparent/Translucent/Opaque
Object is Luminous/Non-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
Smoke
Translucent
Non-luminous
A sheet of plane 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

Page No 114:

Question 3:

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?

Answer:

When a cylinder is held in sunlight, then a circular shadow or a rectangular shadow can be obtained depending on its orientation related to the Sun.

When the top of the cylinder faces the Sun, then the shadow formed is circular. On the other hand, when the side of the cylinder faces the Sun, then the shadow formed is rectangular.

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Question 4:

In a completely dark room, if you hold up a mirror in front of you, will you see your reflection in the mirror?

Answer:

An image is formed due to reflection of light by a plane mirror. In a completely dark room, there is no light present in the room. Thus, no reflection of light takes place by the mirror placed in the room. Hence, no image will get formed by a mirror in a completely dark room.



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