Textbook Solution: Light, Shadows and Reflections | Living Science (Ratna Sagar) for Class 6 PDF Download

Oral Questions For Formative Assessment (P-134)

Q1:
Ans: Speed of light

Q2:
Ans: Non-luminous objects

Q3:
Ans: No. Opaque

Q4:
Ans: Tracing paper, ground glass

Oral Questions For Formative Assessment (P-139)

Q1:
Ans: No, as the light will not be obstructed by the object.

Q2:
Ans: Yes, but we need an object so that it obstructs the light from the luminous body.

Q3:
Ans: In both cases

Q4:
Ans: False. It can be of the same size, smaller, or bigger than the object depending on the distance of the object from the pinhole as compared to the distance of the screen from the pinhole.

Q5:
Ans: True

Q6:
Ans: A red shadow can be formed when a semi-transparent red-coloured glass or plastic sheet is placed in the path of a light source.

Q7:
Ans: The ray of light will be reflected by the plane mirror in a different direction.

For Formative and Summative Assessment (P-140)

Q1:
Ans: b

Q2:
Ans: d

Q3:
Ans: b

Q5:
Ans: c

Q6:
Ans: c

Q7:
Ans: d

Q8:
Ans: a

Part - B

Q1:
Ans: No

Q2:
Ans: Non-luminous

Q3:
Ans: Luminous

Q4:
Ans: True

Q5:
Ans: No

Q6:
Ans: On a new moon day

Q7:
Ans: True

Q8:
Ans: False

Q9:
Ans: Moon

Q10:
Ans: Translucent

Q11:
Ans: Image

Q12:
Ans: No

Q13:
Ans: Yes

Part - C

Q1:
Ans: Light travels from the sun to the earth in 8 minutes. So we see the sun rising 8 minutes after it has actually risen.

Q2:
Ans: Sun, firefly are natural sources of light. Candle, electric bulb are artificial sources of light.

Q3:
Ans: When light falls on a non-luminous object, it gets reflected in different directions. When this reflected light reaches our eyes, we can see the object.

Q4:
Ans: The property of light traveling in straight lines is called rectilinear propagation of light.

Q5:
Ans: Translucent objects are those objects that allow some light to pass through but not enough to enable us to see clearly through them. Examples are butter paper and ground glass.

Q6:
Ans: A shadow is formed when light from a source is obstructed by an opaque object.

Q7:
Ans: During a solar eclipse, the dark side of the moon faces the earth. Therefore, a solar eclipse always occurs on a new moon day.

Q8:
Ans: We can see an image of an object in a plane mirror when light from the object reaches our eyes after reflection from the plane mirror.

Part - D

Q1:
Ans: We depend on light energy for food, oxygen, and fuel because green plants prepare food using the energy of light. Similarly, the energy of all fossil fuels such as petroleum, coal, and natural gas has also been derived from the light energy of the sun.

Q2:
Ans: Take three rectangular pieces of cardboard. Make holes in them at exactly the same level. Make them stand straight on a table using wooden supports. Keep a burning candle on the table, with its flame at the level of the holes. Now adjust the cardboards so that we can see the candle flame through the holes. We will find that the flame can only be seen when the holes are exactly in a straight line. This proves that light travels in straight lines.

Q3:
Ans: (i) A shadow is black in colour.
(ii) It is similar in shape to the object.
(iii) It does not show any details of the object.

Q4:
Ans: a. Region C
b. Region between A and B

Q5:
Ans: The differences between an image and a shadow are:
(i) A shadow is black while an image is of the same colour as the object.
(ii) A shadow is similar in shape to the object, but shows no other details about the object. An image is not only of the same shape as the object but has all the details that the object has.

Q6:
Ans: (See diagram from book): A pinhole camera

Q7:
Ans: (See diagram from book): Reflection of light rays by a plane mirror

HOTS Questions

Q1:
Ans: A translucent object will form a shadow. Darker because no light can pass through an opaque object.

Q2:
Ans: Yes, when there are more than one source of light. A shadow is formed from each light source present in a scene. Therefore, two or more shadows can be formed at the same time by the object.

Q3:
Ans: Black

Q4:
Ans: A pinhole camera forms an image since it is formed by light from the object actually falling on the screen.

Q5:
Ans: Yes, if the distance of the object from the pinhole is smaller than the distance of the screen from the pinhole.