Class 5 General Science (G.Sc.) Notes: Unit-6: Light and sound: Solved Exercise ( MCQs, Questions and Answers)

General Science (G.Sc.) Class 5 Notes

Based on the Single National Curriculum, PK

(New Book/New Syllabus for 2023-2024 Exams and onward)

National Book Foundation
as
Federal Textbook Boards, Islamabad

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"1. Tick ( ✓ ) the Correct Answers"

i. How does light travel in the air? :

(a) In a circle
(b) Along a curve path
(c) Along a straight line
(d) In a dispersed path

... Answer is (c)  Along a straight line
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ii. Which of the following reflects maximum lights?

(a) White paper
(b) Coloured paper
(c) Mirror
(d) Brick wall

... Answer is (c)  Mirror
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iii. Speed of sound is maximum in:

(a) a metal wire
(b) air
(c) water
(d) vacuum

... Answer is (a) a metal wire
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v. When water comes in the way of sound traveling through the air:

(a) sound will stop
(b) sound will slow down
(c) sound will become fast
(d) it has no effect on the speed of sound

... Answer is (c) sound will become fast
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2. "Write Short Answers"

Q(i). What is a transparent object? Write the name of three transparent objects.

Ans:

Transparent Object:- 

The objects through which light can pass completely are called Transparent objects. We can see clearly across them.

Examples: i. glass ii. pure water iii. clear plastic 

Q(ii). When is your shadow the shortest and the longest in the sunlight? 

Ans: 

Shadows are shortest at noon when the sun appears highest in the sky. 

Shadows are the longest in the early morning and late afternoon. When the Sun appears low in the sky. 

Q(iii). The Moon is non-luminous like our Earth. How does it look luminous to us? 

Ans: The Moon is non-luminous like our Earth. It doesn't give off light of its own.  All the light we see is the reflected light of the sun. 

Q(iv). Can you win if you race with your shadow? Tell the reason.

Ans: If we race with our shadow, running away from The Sun, "we shall lose. If we race with our shadow, running toward the Sun, we shall always win. 

Q(v). When a train moves away from you, will the intensity of its sound increase or decrease?

Ans: The intensity of sound decreases with the increase of distance from its source. That's why when a train moves away from us, the intensity of its sound will decrease.

3. "Constructed Response Question"

Q(i). Some animals like hares and rats actually raised their ears. When and why do They do that? 

Ans: Some animals like hares and rats raise their ears;

1. to monitor the environment 

2. detect the enemy 

3. detect the source of the sound. 

Q(ii). Wood and Charcoal are naturally non-luminous objects. Can they be made luminous? How? 

Ans: Wood and charcoal are naturally non-luminous objects. When we burnt them, then they became luminous. 

Q(iii). How can you compare the speed of light and the speed of sound coming from lightning? 

Ans: When lightning Strikes, lightning appears first, while the sound of lightning is heard a few moments later. Because the speed of light is more as compared to the Speed of sound.

4."INVESTIGATE QUESTIONS"

Q1. Have you ever seen the ears of a frog, locust and fish? How do those animals hear sounds?

Ans. 

Frog: 

Frogs have no ears either or at least no outer ear structures. They can still croak, however, and can hear the sounds made by others of their species. The creatures use their mouths as a resonance chamber, thus amplifying sounds.

Locust: 

Unlike a microphone membrane, the eardrum of the locust is a complicated structure that is used to process the information contained in an incoming sound.

Fish: 

Fish hear, but their "ear" is on the inside. Bony fishes detect vibrations through their "ear tones" called otoliths.

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4.  5th Class: Urdu (اُردو) Notes

5.  5th Class: Islamiyat (اسلامیات) Notes

6.  5th Class: Mathematics Notes

7.  Easy English Grammar Notes

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