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WorksheetsSound Grade 8 ICSE
Total questions: 25
Worksheet time: 15mins
Which of these are not true about sound?
Sound is a type of energy.
Sound travels in longitudinal waves.
Sound is produced by vibrations.
Sound, once produced, travels upwards.
Sound travels fastest in low density mediums.
The speed of sound in a medium depends on: (Mark all that apply)
Density
Temperature
Elasticity
Ambient Light
Which of these is true?
The sun gives us light but not sound.
The sun generates sound but it doesn't reach us because sound cannot travel in a vacuum.
The sound that reaches the Earth from the sun is not in the hearable frequency.
In this image, the sound in the purple waves will be ____________ compared to the sound in the black wave (the first wave)
More shrill
Louder
More melodious
One compression and one rarefaction make up a
Time Period
Wavelength
Amplitude
Frequency
Mark all the pairs that are correctly matched:
Frequency - Pitch
High temperature = High wave speed
Amplitude = Loudness
Tension = Loudness
Sushruta has matched the characteristics of a sound wave with their SI unit, but you know she hasn't done all of them right. Mark all the ones that she has done incorrectly.
Frequency - Hertz
Amplitude - A
Wavelength - meter
Wave Speed - m/s
Time Period - Seconds
Surya has tried to match the symbols to the characteristics. As usual, they are not as smart as you and have got some stuff wrong. Mark everything that is wrong.
Wavelength - γ
Wave speed - V
Amplitude - A
Frequency - V
Time Period - T
The number of oscillations completed per unit time by sound. What is this?
Amplitude
Frequency
Wave length
Time Period
Time taken for one complete oscillation in the density of the medium is called the __________ of the wave.
Frequency
Time Period
Wave length
v = 1/T or T = 1/v. These equations indicate the relationship between:
Frequency and Time Period of a wave
Speed and frequency of a wave
Higher the Time Period, _____________ the frequency.
Higher
Lower
v = γυ This is the formula for:
Wave Speed = wavelength * frequency
Wavelength = Time Period * frequency
For the same amplitude, a higher frequency will mean a _________ pitch.
Higher
Softer
The pitch of a sound depends on (mark all that apply)
Tension
Length of air column
Density
Thickness of the string
Temperature of the string
Krishna is wondering which musical instruments owe their shrillness to the length of the air column. Can you help him? Mark all that are right.
Flute
Jal Tarang
Water falling in a bucket
Guitar
All of these instruments get their pitch from the tension of the medium, except one.
Flute
The (a) is the only device that can produce a monotone.
Which of these is true about the loudness of a sound? (Mark all that apply)
Loudness is relative.
Lower the amplitude, louder the sound.
It depends on the distance from the source of the sound.
Larger the surface area of the vibrating object, louder the sound.
Which of these is NOT true about the unit of loudness of sound?
The unit, bel, is named after Alexander Graham Bell.
1 Db = 1/10 * 1B
0 Db is sound energy of the level 10-12 watt / m2
100 Db is the level at which noise pollution begins
A whistle was blown but you didn't hear it. Your friend accused you of deliberately ignoring the sound. Which of these, if true, conclusively proves that you were right. You really could not hear the whistle?
The frequency of the whistle's sound was 22,000 Hz
The friend was over 200 m away when he blew the whistle.
One of these pairs is incorrectly matched. Which one?
< 20 Hz - Infrasonic
> 20,000 Hz - Infrasonic
20 - 20,000 Hz - Human Audible range
The speed of sound in air at 15o C is:
(a)
_____________ is the rapid back and forth movements of a body.
Waveform
Noise
Vibration
Some of these statements are true. Which ones?
A collection of notes is called a tone.
The note at the lowest frequency is called the fundamental tone.
All the tones above the fundamental tone are called overtones.
Tones that have a frequency that is a multiple of the fundamental tone are called harmonics.
