SOUND T & F ICSE CLASS 8

SOUND FILL IN THE BLANKS AND NOTES

SOUND MCQ

Write True Or False

1. Sound waves travel faster in air than in water.

2. Sound waves do propagate in vacuum.

3. The unpleasant sounds are called noises.

4. The amplitude of a sound depends upon the force applied in vibrating the sound producing object.

5. Women have loud voice in comparison to men.

Answers

Write True Or False

1. False

2. False

3. True

4. False

5. False

WORKSHEET

1. Write true or false for each statement

(a) When sound propagates in air, it does not carry energy with it.

Answer. False.

(b) In a longitudinal wave, compression and rarefaction are formed.

Answer. True.

(c) The distance from one compression to nearest rarefaction is called wavelength.

Answer. False.

(d) The frequency is measured in second.

Answer. False.

(e) The quality of a sound depends on the amplitude of wave.

Answer. False.

(f) The pitch of sound depends on frequency.

Answer. True.

(g) Decibel is the unit of pitch of a sound.

Answer. False.

Question 1.

A sound with higher amplitude is a soft sound whereas a sound with lower amplitude is loud.

Answer:

False.

Correct : A sound with higher amplitude is a loud sound whereas a sound with lower amplitude is a soft sound.

Question 2.

The pitch of a sound of string instruments decreases with the decrease in the thickness of the vibrating string.

Answer:

False.

Correct : The pitch of a sound of string instruments decreases with increase in the thickness of the vibrating string.

Question 3.

Pitch of a sound depends on its frequency.

Answer:

True.

Question 4.

The pitch of a stringed instrument depends on the tension in the string.

Answer:

True.

Question 5.

A flute produces sound due to vibration of air column inside it.

Answer:

True.

Question 6.

Music has a disturbing effect on health and behaviour of a person.

Answer:

False.

Correct : Noise has a disturbing effect on health and behaviour of a person.

Question 7.

Sounds below 50 dB cause noise pollution arid are harmful.

Answer:

False.

Correct : Sounds above 80 dB can cause noise pollution and are harmful.

Question 8.

Percussion instruments produce sound due to the vibration of thin metal strips.

Answer:

False.

Correct : Percussion instruments produce sound by a vibrating stretched membrane or by vibration of their whole bodies.

SOUND MCQ ICSE CLASS 8

SOUND FILL IN THE BLANKS AND NOTES

SOUND TRUE AND FALSE

Tick (✔) The correct choice amongest the following

1. Sound is a form of : (a) energy(b) wave(c) disturbance(d) all of these

2. Sound travels fastest in : (a) solids(b) liquids(c) gases(d) vacuum

3. The loudness of a sound (a) amplitude(b) pitch(c) velocity(d) wavelength

4. Loudness is a sensation depending upon : (a) time period(b) phase(c) frequency(d) intensity

5. Hertz is a unit of : (a) time period(b) wavelength(c) frequency(d) wave speed

Answers

Tick (✔) The correct choice amongest the following

1. (a) energy

2. (a) solids

3. (a) amplitude

4. (a) time period

5. (c) frequency

WORKSHEET

Select the correct alternative

(a) Sound can not travel in

1.  solid

2.  liquid

3.  gas

4.  vacuum

(b) When sound travels in form of a wave

1. the particles of medium move from the source to the listener

2.  the particles of medium remains stationary

3.  the particles of medium start vibrating up and down

4.  the particles of medium transfer energy without leaving their mean positions.

(c) The safe limit of loudness of audible sound is

1.  0 to 80 dB

2.  above 80 dB

3.  120 dB

4.  above 120 dB

(d) The unit of loudness is

1.  cm

2.  second

3.  hertz

4.  decibel

(e) In a piano, pitch is decreased by

1.  using thicker string

2.  increasing tension

3.  reducing length of string

4.  striking it hard
   

1. Loudness of a sound depends on the a. the wavelength of sound. b. volume of air around the vibrating body. c. time. d. none of these Answer:d. none of these

2.The pitch of a sound increases with increase in its a. frequency. b. loudness. c. amplitude. d. time period. Answer:a. frequency.

3.The pitch of a flute can be increased by

a. increasing the length of its vibrating air column.

b. decreasing the length of its vibrating air column.

c. increasing the length of its vibrating string.

d. decreasing the length of its vibrating string.

Answer:

b. decreasing the length of its vibrating air column.

4.A sound produced by guitar and violin with the same pitch and loudness is distinguished by its

a. frequency.

b. amplitude.

c. timbre.

d. time period.

answer:

c. timbre.

5.Which of the following properties of sound is responsible for its loudness?

a. frequency

b. pitch

c. amplitude

d. quality

Answer:

c. amplitude

6.Musical sounds are caused due to –

a. regular vibrations.

b. irregular vibrations.

c. damped vibrations.

d. none of these

Answer:

a. regular vibrations.

7.The sound that never changes in pitch, volume, speed or timbre is known as –

a. monologue.

b. monolingual.

c. monophony.

d. monotone.

Answer:

d. monotone.

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HEAT MCQ ICSE CLASS 8

Tick (✔) The correct choice amongest the following

1. When a bimetallic strip (brass and invar) is heated : (a) it remains straight (b) it bends with brass on convex side (c) it bends with invar on convex side (d) it does not have a definite shape

2. A bimetallic strip is not used in : (a) thermostat(b) pendulum clock(c) fire alarm(d) electric iron

3. In solids thermal expansion is of : (a) three types(b) four types(c) five types(d) all of these

4. Linear expansion does not depend on the : (a) nature of material (b) original length of the body (c) the increase in temperature (d) original surface area of the body

Answers

Tick (✔) The correct choice amongest the following

1. (b) it bends with brass on convex side

2. (b) pendulum clock

3. (a) three types

4. (d) original surface area of the body

WORKSHEET

Select the correct alternative 

(a) In evaporation

1. all molecules of liquid begin to escape out

2.  only the molecules at the surface escape out

3.  the temperature of liquid rises by absorbing heat from surroundings.

4.  the molecules get attracted within the liquid.

(b) The rate of evaporation of a liquid increases when :

1.  temperature of liquid falls

2.  liquid is poured in a vessel of less surface area

3.  air is blown above the surface of liquid

4.  humidity increases.

(c) During boiling or vaporization

1.  all molecules take part

2.  temperature rises

3.  no heat is absorbed

4.  the average kinetic energy of molecules increases.

(d) The boiling point of a liquid is increased by

1.  increasing the volume of liquid

2.  increasing the pressure, on liquid

3.  adding ice to the liquid

4.  decreasing pressure on liquid.

(e) Two rods A and B of the same metal, but of length 1 m and 2 m respectively, are heated from 0°C to 100°C. Then

1.  both the rods A and B elongate the same

2.  the rod A elongates more than the rod B

3.  the rod B elongates more than the rod A

4.  the rod A elongates, but the rod B contracts.

(f) Two rods A and B of the same metal, same length, but one solid and the other hollow, are heated to the same rise in temperature.Then

1.  the solid rod A expands more than the hollow rod B

2.  the hollow rod B expands more than the solid rod A

3.  the hollow rod B contracts, but the solid rod A expands

4.  both the rods A and B expand the same.

(g) A given volume of alcohol and the same volume of water are heated from the room temperature to the same temperature then.

1.  alcohol contracts, but water expands

2.  water contracts, but alcohol expands

3.  water expands more than alcohol

4.  alcohol expands more than water.

(h) The increase in length of a metal rod depends on

1.  the initial length of the rod only

2.  the rise in temperature only

3.  the material of rod only

4.  all the above three factors.

(i) The correct statement is

1.  Iron rims are cooled before they are placed on the cart wheels.

2.  A glass stopper gets tighten on warming the neck of the bottle.

3.  Telephone wires sag in winter, but become tight in summer.

4.  A little space is left between two rails on a railway track.

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Write True Or False

1. During boiling, the temperature of the liquid does not change.

2. A bimetallic strip is used in a thermostat.

3. The expansion in volume is called superficial expansion.

4. The iron girders of a bridge contract in summer and expand in winter.

Answers

Write True Or False

1. False

2. True

3. False

4. True

WORKSHEET

1. Write true or false for each statement

(a) Evaporation is rapid on a wet day.

Answer. False.

(b) Evaporation takes place only from the surface of liquid.

Answer. True.

(c) All molecules of a liquid take part in the process of evaporation.

Answer. False.

(d) Temperature of a liquid rises during boiling or vaporization

Answer. False.

(e) All molecules of a liquid take part in boiling.

Answer. True.

(f) Boiling is a rapid phenomenon.

Answer. True.

(g) All solids expand by the same amount when heated to the same rise in temperature.

Answer. False.

(h) Telephone wires are kept tight between the two poles in winter.

Answer. True.

(i) Equal volumes of different liquids expand by the different amount when they are heated to the same rise in temperature.

Answer. True.

(j) Solids expand the least and gases expand the most on being heated.

Answer. True.

(k) A mercury thermometer makes use of the property of expansion of liquids on heating.

Answer. True.

(l) Kerosene contracts on heating.

Answer. False.

Write true or false. Correct the false statements.

Question

1.Boiling causes cooling.

Answer:False.

Correct : Evaporation causes cooling.

Question

2.Wet clothes dry because the water in them boils to its vapour state.

Answer:False.

Correct : Wet clothes dry because the water in them evaporates to its vapour state.

Question

3.Boiling occurs in the whole volume of a liquid whereas evaporation occurs only at the surface of a liquid.

Answer:True

Question

4.Water evaporates at all temperatures.

Answer:True

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Select the Odd and Out Giving reason

1. Thermal expansion, boiling, superficial expansion, volume expansion.

2. Evaporation is fast, evaporation occurs at all temperatures, evaporation is energy supplied by surroundings, no bubbles are formed in evaporation.

3. Solids, wood, liquids, gases.

Answers

Select the Odd and Out Giving reason

1. Boiling : others are types of expansion

2. Evaporation is fast : is not a property of evaporations others are

3. Wood : others are three states of matter.

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Fill in The Blanks

1. Evaporation occurs at ...........................

2. In solids thermal expansion is of ........................., ......................... and ............................

3. ............................. is an expansion when a solid is heated there is a change in its volume.

4. A bimetallic strip is made from .........................which expand by different amounts when heated.

5. A ........................ is a metal pin or bolt used for fastening metal plates

Answers

Fill in The Blanks

1. any temperature

2. linear, superficial, cubical

3. cubical expansion

4. two thin strip of metal

5. rivet

WORKSHEET

2. Fill in the blanks 

(a) Boiling occurs at a fixed temperature.

(b) Evaporation takes place at all temperature.

(c) The molecules of liquid absorb heat from surroundings in evaporation.

(d) Heat is absorbed during boiling.

(e) Cooling is produced in evaporation.

(f) A longer rod expands more than a shorter rod on being heated to the same temperature.

(g) Liquids expand more than the solids.

(h) Gases expand more than the liquids.

(i) Alcohol expands more than water.

(j) Iron expands less than copper.

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Match The Columns

1. 1.Thermal expansion fast 2.Bimetallic strip  electric iron 3.Boiling sensation of hotness or coldness 4.Evaporation slow 5.Heat Gravesad’s ball and ring experiment

Answers

Match The Columns

1. 1.Gravesad’s ball and ring experiment

2.electric iron

3.fast

4.slow

5.sensation of hotness or coldness

WORKSHEET

3. Match the following

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