General Science 5th Class Chapter 6 Light and Sound Solved Exercise

General Science

5th Class

Chapter 6

Light and Sound

Questions

1. Encircle the correct option.

i. How does light travel in air?

a. In a circle        b. Along curved path

c. Along a straight line        d. In dispersed path

ii. Which object reflects maximum light?

a. White paper        b. Coloured paper        c. Mirror        d. Brick wall

iii. Speed of sound is maximum in:

a. a metal wire        b. air        c. water        d. vacuum

iv. Which of the following sounds is called noise?

a. Sound of a flute        b. Rustling of leaves

c. Pressure horn        d. Chirping of birds

v. When water comes in the way of sound travelling through air:

a. sound will stop        b. sound will slow down

c. sound will become fast        d. no effect on the speed of sound

2. Write short answers.

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

Ans.

The objects through which light can pass completely are called transparent objects. We can see clearly across them. For example, mirror, glasses and glass filled with water are transparent thing.

ii. When is your shadow the shortest and longest in the sunlight.

Ans.

In morning and evening the shadows are longest, while in noon our shadow is shortest in the sunlight.

iii. The Moon is non-luminous like our Earth. How does it looks luminous to us?

Ans.

The moon is non-luminous object like our Earth but it looks luminous due to sunlight, it absorbs sunlight and reflects to make itself bright.

iv. Can you be a winner while running with your shadow? Give the reason also.

Ans.

No we cannot win with our shadow because shadow forms beyond the object (body).

v. When a train is moving away from you, will the intensity of its sound increase or decrease?

Ans.

When a train is moving away from you, intensity of sound will decrease.

3. Constructed Response Questions:

i. "Ears are raised" is a phrase in Urdu. The ears of some animals such as hare and rat are actually raised up? When and why?

Ans. The hare and rat rise up their ears due to presence of predator around their surrounding.

ii. Wood and charcoal are naturally non-luminous objects. Can they be made luminous? How?

Ans. Yes wood and charcoal can be luminous by ignition of match stick.

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

Ans. The speed of light is greater than speed of sound. This is the reason that we see the light first then its sound during lightning.

iv. Mark () for pleasant sounds and mark () for unpleasant sounds in the given pictures.

Ans. 

4. Investigate:

i. How you seen the ears of a frog, locust and fish? How do these animals hear sounds?

Ans. Frog, locust and fish do not have ears, but they can hear the sound by ear like internal structure and skin.

ii. By using torch, find out how much light passes from the objects given below?

Ans. 

5. Project:

i. Make a pinhole camera by using cardboard box, wax paper or tissue paper. Observe the image formed by it. On which principle of light does it works? What are the characteristics of images?

Ans.

ii. Make a simple musical instrument using a wooden board, iron nails, thin steel wires of different lengths and a hammer. On which principle foes this instrument work? Observe also the intensity of sound produced by it.

Ans.