Class 5 Science Lesson 7

 Exercise – 1 (Light)

1. If the statement given below is correct, put a tick mark (✓) and if it is wrong, put a cross mark (x):

(a) Objects are visible due to light. ✓

(b) The flame of a fire is a nonluminous object. x

(c) Air is an opaque substance. x

(d) Light can easily penetrate through the stone. x

(e) Rainbows can be seen when the sun shines after the rain. ✓

2. Fill in the blanks by choosing the appropriate word.

Nonluminous, man-made, seven, natural, transparent, five

(a) Sun is the source of natural light.

(b) Wood is a nonluminous object.

(c) An object that lets the light pass through it easily is called a transparent object.

(d) Rainbow has seven colours.

(e) Torchlight is a man-made source of light.

3. Choose the correct option for the question given below:

(a) Which of the given objects is luminous?

👉 B. Sun

(b) How many colours are there in a rainbow?

👉 C. seven

(c) If you wish to plant a plant that needs a lot of sunlight in your room, which of the following windows would be suitable?

👉 B. window with glass pane

(d) Your mother complains that she has to face glaring sunrays while riding a scooter on the way to her office and they hurt her eyes. Which advice would you give her?

👉 B. wear spectacle with translucent lenses

(e) Why is there light on a cloudy day even if the sun is not visible?

👉 C. because clouds are translucent

4. Write the answers to the following questions:

(a) Write the definition of a luminous object with two examples.

👉 A luminous object is an object that produces its own light. Examples are the Sun and a candle flame.

(b) Distinguish between transparent and opaque objects.

👉 Transparent objects allow light to pass through them so that we can see objects clearly through them, like glass and water. Opaque objects do not let light pass through and block the light, like wood and stone.

(c) Write two ways to make the transparent glass placed in the window translucent.

👉 The transparent glass can be made translucent by applying frosted glass film or rubbing soap on the glass surface.

(d) Why does a rainbow appear only after rain?

👉 A rainbow appears after rain because sunlight passes through raindrops, which act like tiny prisms and separate the white light into seven colours.

(e) Why is it difficult to drive on the road when there is a thick fog?

👉 It is difficult to drive because fog scatters the light, reducing visibility and making it hard to see clearly.

(f) Your little sister wants to see a rainbow on a day when it is not raining. Explain what you would do to satisfy her curiosity.

👉 I would spray water mist in the air on a sunny day so that the sunlight can refract and form a rainbow for her to see.

Exercise – 2 (Sound)

1. If the statement given below is correct, put a tick mark (✓) and if it is wrong, put a cross mark (x):

(a) Sound is a form of energy. ✓

(b) Sound originates itself from the source of the sound. x

(c) A medium is required for the transmission of sound. ✓

(d) The thin strings of the guitar produce a shrill sound. ✓

(e) Noisy factories should be built away from human habitation. ✓

2. Fill in the blanks in the sentences below with suitable words:

sharper, good etiquette, vibrate, mental illness, sound, hoarse

(a) Radio is a source of sound.

(b) To produce sound, the object must vibrate.

(c) Good etiquette must be followed even inside the classroom.

(d) Beating a metal object produces sharper sound than beating a wooden object.

(e) Staying in a noisy place for a long time may cause mental illness.

3. Choose the correct option for the following questions:

(a) Which of the following is the source of sound?

👉 iii. radio

(b) Which of the following media is not suitable for the transmission of sound?

👉 iv. vacuum

(c) Which of the following actions causes vibration in an object?

👉 i. beating it

(d) Which of the following types of sound is harmful to health?

👉 iv. loud

(e) In the absence of the teacher in the class, someone is drumming the desk and singing a song. Some people are making loud noises. Because of this, students who are trying to read are not able to do so. Which of the following would be the best way to solve this problem?

👉 iv. follow good behavior to avoid unnecessary noise in the class

4. Write the answers to the following questions:

(a) What is sound?

👉 Sound is a form of energy produced by vibrating objects.

(b) How does sound originate from the source of the sound?

👉 Sound originates when an object vibrates and causes the particles around it to vibrate, producing sound waves.

(c) Why does the drum make a soft sound when it is struck slowly and a loud sound when it is struck hard?

👉 The drum makes a soft sound when struck slowly because it vibrates less forcefully, and a loud sound when struck hard because it vibrates more forcefully.

(d) What are the sources of noise around your house? Prepare a list.

👉 Sources of noise around the house can be vehicles, radios, televisions, construction work, animals, and people talking loudly.

(e) There has been a traffic jam on the road outside the hospital for a long time. Everyone is in a hurry, so everyone is honking loudly. Write down the solutions to the problem that occurs in such a situation.

👉 To reduce noise in traffic jams, people should avoid unnecessary honking, follow traffic rules, and authorities should manage traffic flow better.

Exercise – 3 (Electricity)

1. If the statement given below is correct, put a tick mark (✓) and if it is wrong, put a cross mark (x):

(a) Nothing happens if electrical equipment is touched with wet hands. x

(b) A conducting wire is a source of electricity. x

(c) The function of the switch is to turn the light on and off. ✓

(d) Current flows in an open circuit. x

(e) We should not put our finger in the electric socket. ✓

2. Fill in the blanks of the sentences with suitable words:

Insulator, electrical equipment, electrical circuit, on, electricity, off

👉

(a) Dry cell is a source of electricity.

(b) A path consisting of a source of electricity, conductors, switches, and electrical equipment is called an electrical circuit.

(c) If bare wire is seen, it should be covered with insulator.

(d) Switch is on in the closed circuit.

(e) Small children should not play with electrical equipment.

3. Choose the correct option for the questions below:

(a) A lamp placed in an electric circuit does not light. Which of the following could be the reason?

👉 i. switch is off

(b) What is the function of a conducting wire in an electric circuit?

👉 ii. to pass electricity

(c) If an electric bulb does not light, what should be done?

👉 iii. take the help of a knowledgeable person

(d) Without which of the following materials is an electrical circuit incomplete?

👉 i. battery

(e) Which of the following events would you stop doing if you see them?

👉 iii. little brother putting an electric wire in his mouth

(f) In which of the following figures does the bulb light up?

👉 iii.

4. Write the answers to the following questions:

(a) Write the definition of an electric circuit.

👉 An electric circuit is a closed path made up of a source of electricity, conducting wires, switches, and electrical equipment through which electric current flows.

(b) Write two differences between closed circuit and open circuit.

👉 A closed circuit has a complete path and current flows through it. An open circuit has a break in the path and no current flows.

(c) Write two precautions to be taken while using electricity.

👉 Do not touch electrical devices with wet hands and always cover bare wires with insulation.

(d) Write a reason why a light bulb connected to a circuit that has a switch in the off position does not light.

👉 Because the circuit is open and current cannot flow when the switch is off.

(e) What is required to complete an electric circuit?

👉 A complete conducting path including a source, wires, and a load (like a bulb) is required.

(f) What must be done to light the bulb in the circuit diagram given below?

👉 The switch must be turned on to complete the circuit and allow current to flow so the bulb can light.