Living Science 2020 2021 Solutions for Class 6 Science Chapter 12 Light, Shadows And Reflections are provided here with simple step-by-step explanations. These solutions for Light, Shadows And Reflections are extremely popular among Class 6 students for Science Light, Shadows And Reflections Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science 2020 2021 Book of Class 6 Science Chapter 12 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science 2020 2021 Solutions. All Living Science 2020 2021 Solutions for class Class 6 Science are prepared by experts and are 100% accurate.
Page No 141:
Question 1:
Which is greater−the speed of light or the speed or sound?
Answer:
Speed of light in air is 3108 m/s and the speed of the sound in air is 332 m/s. Hence, the speed of the light is greater than the speed of the sound.
Page No 141:
Question 2:
Which objects can you not see in a dark night−luminous objects or non-luminous objects?
Answer:
We can see an object when the light rays get reflected by the object and fall on our eyes. In a dark night, there will not be any light rays, so we will not able to see a non-luminous object. But we can see a luminous object in a dark night because of light rays coming from the object.
Page No 141:
Question 3:
Is it possible to see through an object that does not allow light to pass through it? What are such object called?
Answer:
No, it is not possible to see through an object if it does not allow light rays to pass through it. Such objects are known as Opaque object.
Page No 141:
Question 4:
Give two examples of objects that allow light to pass through but not enough for you to see through them clearly.
Answer:
Glass and water are the two examples of such objects which allow light to pass through but not enough to see through them clearly.
Page No 146:
Question 1:
Suppose there is an object around which light could bend, like water flowing around a stone in its path. Would such an object form a shadow? Justify your answer.
Answer:
Shadows are formed when the path of light rays is obstructed by something opaque. If light rays can bend around an object that means they will pass around the object and the path of the light rays will not be obstructed. Hence, such object will form no shadow.
Page No 146:
Question 2:
Can a luminous object in a dark room cast a shadow? Justify your answer.
Answer:
The luminous object can not cast a shadow in a dark room. Because it can't block the path of its own light and there is no other light source in the room.
Page No 146:
Question 3:
In which of these cases does a solar eclipse occur?
a. when the moon comes in between the earth and the sun
b. when the shadow of the moon falls on the earth
Answer:
In both cases, a solar eclipse occurs. When the moon comes in between the earth and the sun, the moon blocks the light rays coming from the sun. Due to this, the shadow of the moon falls on the earth, which causes a solar eclipse on the earth.
Page No 146:
Question 4:
The image formed by a pinhole camera is of the same size as the object. True or false? justify your answer.
Answer:
The given statement is False. A pinhole camera can form an image bigger than the object too. Pinhole camera forms real, upside down and the size of the image depends on the distance between the pinhole and the screen on which image is formed. Pinhole camera works on the principle of rectilinear propagation of light. Light falls from the object through the pinhole and forms a smaller image on the translucent screen if the pinhole and the screen are closer to each other. If the distance between the pinhole and the screen is increased then it can form an even bigger image than the object.
Page No 146:
Question 5:
An image formed by a plane mirror is of the same color as the object. True or false?
Answer:
The given statement is true. A plane mirror reflects the light at the same angle at which it falls on it. So, it forms an image of the exact same color, shape, and size as of the object.
Page No 146:
Question 6:
Under what circumstances can a red shadow be formed?
Answer:
A red shadow can never be formed. A shadow is formed due to the absence of light rays. When an object blocks the path of light rays, a shadow of the object is formed behind the object in an area over which light rays are obstructed. So, there is no chance that the color of the shadow is red.
Page No 146:
Question 7:
What happens to the direction of a ray of light after it falls on a plane mirror?
Answer:
When a ray of light falls on a plane mirror, it changes its direction because it gets reflected from the surface of the mirror at the same angle at which it falls on the surface.
Page No 147:
Question 1:
Light is
(a) visible and also makes objects on which it falls visible.
(b) invisible but makes objects on which it falls visible.
(c) invisible but becomes visible when it falls on an object.
(d) sometimes visible and sometimes invisible but it always makes objects on which it falls visible.
Answer:
(b) invisible but makes objects on which it falls visible.
Light is invisible by itself but makes visible the objects on which it falls.
Page No 147:
Question 2:
The shape and size of a shadow depends on
(a) the shape and size of the object.
(b) the position of the source of light.
(c) the distance between the source of light and object.
(d) all of the above
Answer:
(d) all of the above.
The shape and the size of a shadow depends upon the shape and size of the object, the position of the source of light and the distance between the source of light and the object.
Page No 148:
Question 3:
Which of these is not a source of light?
(a) sun
(b) moon
(c) lighted candle
(d) stars
Answer:
(b) moon
The moon is not a source of light. It shines by reflected light.
Page No 148:
Question 4:
Which of these is not a property of an image formed by a place nirror?
(a) It is of the same shape as the object.
(b) It does not show any details in the object.
(c) it is of the same colour as the object.
(d) It is of the same size as the object.
Answer:
(b) It does not show any details in the object,
An image formed by a plane mirror is of the same shape, size and colour as the object. It also shows the same details as in the object.
Page No 148:
Question 5:
Which of these is true for an image?
(a) It is formed when light is blocked by an opaque object.
(b) It is formed when light passes through a transparent object.
(c) It is of the same shape and colour as the object.
(d) It is always black.
Answer:
(c) It is of the same shape and colour as the object.
An image has the same shape and colour as the object.
Page No 148:
Question 6:
A shadow is formed when
(a) light from a luminous object reaches our eyes.
(b) light from a luminous object reaches our eyes after reflection.
(c) light from a luminous object is prevented from reaching our eyes by another object.
(d) light from a luminous object reaches our eyes after passing through a transparent object.
Answer:
(c) light from a luminous object is prevented from reaching our eyes by another object.
A shadow is formed when light from a source is blocked by an opaque object and the light does not reach our eyes.
Page No 148:
Question 7:
The image formed in a pinhole camera is always
(a) erect and of the same size as the object.
(b) erect and either smaller or bigger or of the same size as the object.
(c) inverted and of the same size as the object.
(d) inverted and either smaller or bigger or of the same size as the object.
Answer:
(d) inverted and either smaller or bigger or of the same size as the object.
The image obtained by a pinhole camera is an inverted image and it can be either smaller, larger or of the same size as the object.
Page No 148:
Question 8:
A lunar eclipse occurs when the
(a) earth is between the sun and the moon.
(b) moon is between the sun and the earth.
(c) sun is between the earth and the moon.
(d) in all the above situations
Answer:
(a) earth is between the sun and the moon.
A lunar eclipse occurs when the earth is between the sun and the moon.
Page No 148:
Question 1:
Can you name anything that can travel faster than the speed of light?
Answer:
Nothing can travel faster than speed of light in vacuum/free space.
Page No 148:
Question 2:
Are most objects around us luminous or non-luminous?
Answer:
Most objects around us are non-luminous. Non-luminous objects do not emit their own light, but may shine by reflecting light falling on them.
Page No 148:
Question 3:
Are stars luminous or non-luminous?
Answer:
Stars are luminous as they emit their own light.
Page No 148:
Question 4:
We depend on light energy for our food. True or false?
Answer:
True. We depend upon light energy for food. We all depend either directly or indirectly on the food prepared by plants through photosynthesis in the presence of sunlight.
Page No 148:
Question 5:
Can a completely transparent object cast a shadow?
Answer:
No, a completely transparent object cannot cast a shadow.
Page No 148:
Question 6:
When does a solar eclipe occur−on a new moon day or on a full moon day?
Answer:
The solar eclipse occurs on a new moon day.
Page No 148:
Question 7:
A beam of light consists of several rays. True or false?
Answer:
True, a beam of light consists of several rays.
Page No 148:
Question 8:
Light can travel through a bent tube just like water can. True or false?
Answer:
False, light cannot bend along the tube like flow of water through a tube.
Page No 148:
Question 9:
Which of these is luminous−sun, earth or moon?
Answer:
Sun is luminous. While, both earth and moon are non-luminous and shine because of the sunlight falling on them.
Page No 148:
Question 10:
If you can see the faint glow of a lighted torch through an object, but not the torch itself, is the substance opaque, translucent or transparent?
Answer:
If one can see the faint glow of torch, but are unable to view the torch itself, then such an object is classified as translucent.
Page No 148:
Question 11:
Which of these is formed by light reflected by an object−image or shadow?
Answer:
An image is formed when light is reflected from an object.
Page No 149:
Question 12:
Can a shadow be formed without a screen?
Answer:
No, shadow cannot be formed without a screen.
Page No 149:
Question 13:
Can an image be formed without a screen?
Answer:
Image can be formed without a screen, as it is formed when the reflected light from an object reaches our eyes.
Page No 149:
Question 1:
We see the sun rising 81/4 minutes afte it has actually risen. Why?
Answer:
The distance between earth and sun is 1485 lakh kilometres. Due to this, sunlight takes 81/4 minutes of time to reach earth. Thus, we see the sun rising 81/4 minutes after it has actually risen.
Page No 149:
Question 2:
Name two natural sources of light and two human-made sources of light.
Answer:
The two natural sources of light are sun and fireflies. Man-made light sources are the electric bulb and the candle.
Page No 149:
Question 3:
How do we see non-luminous objects?
Answer:
When light falls on a non-luminous object, it reflects light in different directions. When this light reaches our eye, we are able to see the object.
Page No 149:
Question 4:
What is meant by 'rectilinear propagation of light'?
Answer:
Light travels along a straight line, this property of light is called as rectilinear propagation of light.
Page No 149:
Question 5:
What are 'translucent' objects? Give two examples.
Answer:
Translucent objects are the ones through which light is only partially transmitted. Butter paper and thin plastic sheets are translucent objects.
Page No 149:
Question 6:
When is a shadow formed?
Answer:
A shadow is formed when the light from a source is obstructed by an opaque object.
Page No 149:
Question 7:
Why does a solar eclipse always occur on a new moon day?
Answer:
A solar eclipse occurs when the sun, the moon and the earth are in straight line, with the moon between the sun and the earth. Therefore, during the solar eclipse, the dark side of the moon faces the earth. It occurs on a new moon day.
Page No 149:
Question 8:
When can you see an image of an object in a plane mirror?
Answer:
You can see an image in a plane mirror if an object is placed in front of the plane mirror.
Page No 149:
Question 1:
We depend on light energy for food and fuel. Explain.
Answer:
We know that green plants prepare their food using sunlight, via photosynthesis. All animals including humans rely either directly or indirectly on plants for food. Thus, we depend upon light for food.
For fuel, we use either coal or petroleum. The former is the fossilized remains of plants and trees. These plants and trees store energy in them from sunlight. In the same way, the microorganisms that have turned into oil and petroleum, depended either directly on indirectly on sunlight. Thus, we also depend upon light for fuel.
Page No 149:
Question 2:
Describe a simple experiment to show that light travels in straight lines.
Answer:
Take three cardboard pieces of similar dimension and make a hole in the centre of each. Align these three cardboard parallel to each other in such a way that all the holes are exactly along the same line. Now, take a lit candle, align it at one end and view the candle from the other end.
You will only be able to see the candle if the holes in the cardboard are all in a straight line. Even if one cardboard is moved to the left or right, your view of the candle will be blocked. This shows that light travels in a straight line.
Page No 149:
Question 3:
List three properties of a shadow.
Answer:
Three properties of a shadow are as follows:
(1) The shape of the shadow depends on the shape of the object and the position of the light source.
(2) The colour of the shadow is always black or grey, independent of object.
(3) Apart from shape of an object, no other detailing of the object can be viewed in the shadow.
Page No 149:
Question 4:
Draw a diagram to show the eclipse of the sun. Mark the areas where you can see
(a) total solar eclipse.
(b) partial solar eclipse.
Answer:
The following diagram shows a solar eclipse and also indicates regions of partial and total eclipse.
Page No 149:
Question 5:
In what ways is an image different from a shadow?
Answer:
The differences between image and shadow are:
| Image | Shadow |
| Image has the same colour as the object. | Shadow is always black or grey, independent of object. |
| An image has not only the same shape as an object but also all the details similar to that of the object. | The shape of shadow is similar to that of an object, but has no other details visible. |
Page No 149:
Question 6:
Draw a diagram to show the formation of the image of a disant tree by a pinhole camera.
Answer:
A pinhole camera showing the formation of the image of a distant tree is shown in the figure below:
Page No 149:
Question 7:
Draw a diagram to show reflection of a ray of light by a plane mirror.
Answer:
The diagram showing reflection of light from a plane mirror is shown below:
Page No 149:
Question 1:
Which of these−a completely transparent object or a translucent object−will form a shadow? Will the shadow formed by an opaque object be darker or lighter than this shadow?
Answer:
Among completely transparent and a translucent object only a translucent object will form a shadow. Shadow formed by an opaque object will be darker than a translucent object. This is because an opaque object will completely block the light, while translucent will allow some light to pass through it and not completely block out the light.
Page No 149:
Question 2:
Can an object form two or more shadows at the same time? How?
Answer:
Yes, an object can form more than one shadow at a time. If an object is illuminated from more than one direction by lights, we can have more than one shadow. For example, if you are lit from two different directions, you will see two shadows.
Page No 149:
Question 3:
What will be the colour of a shadow formed in red light?
Answer:
The colour of a shadow formed from red light source will be black in colour if the object is completely opaque.
Page No 149:
Question 4:
Does a pinhole camera form an image or a shadow of an object? Justify your answer.
Answer:
A pinhole camera forms an image of an object. The image is the region where light coming from the object is focussed by the pinhole on to a screen. The image formed by a pinhole camera is inverted compared to the object, but it has the same colour as the object. In addition, the image has all the details of the object. Hence, we can confirm that a pinhole camera forms an image, not a shadow.
Page No 149:
Question 5:
Can a pinhole camera form an image which is biger than the object? If yes, explain with a diagram.
Answer:
Yes, a pinhole can form an image which is bigger than the object. Observe the figure below.
As the distance d between the screen and the pinhole increases, the size of the image formed by the pinhole camera increases.
Page No 149:
Question 1:
Professor Photon is a scientist. He is designing a rocket to take him to the sun. His colleague Professor Spark tells him that he and the rocket will burn out when they reach near the sun. Professor Photon has an answer to this - he says that he will launch the rocket so that it reaches the sun during a total solar eclipse.
Is Professor Photon's logic correct? Give reason.
Answer:
No, Professor Photon's logic is incorrect. Because during a solar eclipse, the sun remains as it is, only the path of the light rays coming from the sun is blocked by the moon. When the professor will reach nearby the sun there will not anything that can block the sunlight coming from the sun. Hence, he will surely burn out along with his rocket.
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