Sound - Olympiad Level MCQ, Class 9 Science - Class 9 MCQ

# Sound - Olympiad Level MCQ, Class 9 Science - Class 9 MCQ

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## 25 Questions MCQ Test - Sound - Olympiad Level MCQ, Class 9 Science

Sound - Olympiad Level MCQ, Class 9 Science for Class 9 2024 is part of Class 9 preparation. The Sound - Olympiad Level MCQ, Class 9 Science questions and answers have been prepared according to the Class 9 exam syllabus.The Sound - Olympiad Level MCQ, Class 9 Science MCQs are made for Class 9 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for Sound - Olympiad Level MCQ, Class 9 Science below.
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Sound - Olympiad Level MCQ, Class 9 Science - Question 1

### The SI unit of frequency is :

Sound - Olympiad Level MCQ, Class 9 Science - Question 2

### If the frequency of a wave is 25 Hz, the total number of compressions and rarefactions passing through a point in 1 second is

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 2
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Sound - Olympiad Level MCQ, Class 9 Science - Question 3

### Time period of a wave in a medium is the time taken by:

Sound - Olympiad Level MCQ, Class 9 Science - Question 4

Amplitude of a longitudinal wave in a medium:

Sound - Olympiad Level MCQ, Class 9 Science - Question 5

Non-mechanical (electromagnetic) wave can propagate in :

Sound - Olympiad Level MCQ, Class 9 Science - Question 6

The linear distance between a compression and a rarefaction or a crest and a trough is :

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 6
The distance between 2 consecutive compressions and rare faction is called wavelength.
so, linear distance between a compression and rarefaction is lambda÷2
Sound - Olympiad Level MCQ, Class 9 Science - Question 7

A longitudinal wave travels in water from west to east. The direction which the particles of medium move:

Sound - Olympiad Level MCQ, Class 9 Science - Question 8

A stretched string is plucked gently to produce a note. The string is producing:

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 8
Waves in Stretched Strings. A string is a tight wire. When it is plucked or bowed, progressive transverse waves travel along the wire and is reflect at the fixed ends. A progressive sound wave is produced in the surrounding air having a frequency equal to that of the stationary wave in the string.
Sound - Olympiad Level MCQ, Class 9 Science - Question 9

A stretched slinky is given a sharp push along its length. A wave travels from one end to another. The wave

so produced is :

Sound - Olympiad Level MCQ, Class 9 Science - Question 10

A longitudinal sound wave in air consists:

Sound - Olympiad Level MCQ, Class 9 Science - Question 11

The density of air at some point in a longitudinal sound wave is minimum at an instant. The pressure of air

at that point is :

Sound - Olympiad Level MCQ, Class 9 Science - Question 12

Which of the following is an elastic wave?

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 12
Elastic wave. Elastic wave, motion in a medium in which, when particles are displaced, a force proportional to the displacement acts on the particles to restore them to their original position
and sound wave is similar to it.
Sound - Olympiad Level MCQ, Class 9 Science - Question 13

Infrasonic vibrations have frequency:

Sound - Olympiad Level MCQ, Class 9 Science - Question 14

The range of sonic waves is between:

Sound - Olympiad Level MCQ, Class 9 Science - Question 15

The sound waves having a frequency more than 20,000 Hz are called:

Sound - Olympiad Level MCQ, Class 9 Science - Question 16

The animal which cannot hear ultrasonic waves is :

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 16
Cow cannot hear ultra sound waves. As we know that ultrasound wave have higher frequencies than normal sound wave, but they also have shorter wavelengths. Humans  cannot  hear ultra sound same as Cow also cannot hear ultra sound waves because of frequency ranging between 20Hz to 20 KHz (20,000 Hz). Hence, Ultrasound  cannot be hear by human as same as Cow also cannot hear ultra sound.
Sound - Olympiad Level MCQ, Class 9 Science - Question 17

The bat hunts it prey by emitting and receiving reflected:

Sound - Olympiad Level MCQ, Class 9 Science - Question 18

A sonic boom is produced in the air when an aircraft flies at a speed:

Sound - Olympiad Level MCQ, Class 9 Science - Question 19

Sound travels fastest in :

Sound - Olympiad Level MCQ, Class 9 Science - Question 20

A boy sitting in a boat fires a gun. An observer P is at a distance of 50 m from the boat. Another observer

Q is a diver, who is 50 m under water. Both hear the sound of gun:

Sound - Olympiad Level MCQ, Class 9 Science - Question 21

When the lightning strikes, we hear multiple of cracks of thunder. These multiple reflections of sound are called:

Detailed Solution for Sound - Olympiad Level MCQ, Class 9 Science - Question 21
Echos are sound waves reflecting on an object to be hear back. Reverberations are sounds that come in groups or are coming after a short interval. So during thunder we mostly experience this.
Sound - Olympiad Level MCQ, Class 9 Science - Question 22

Hearing of repetition of sound after reflection from a distant object is called:

Sound - Olympiad Level MCQ, Class 9 Science - Question 23

For hearing an echo the minimum distance should be :

Sound - Olympiad Level MCQ, Class 9 Science - Question 24

An echo is heard only, if the original sound after reflection should reach the ear in :

Sound - Olympiad Level MCQ, Class 9 Science - Question 25

A bullet is moving at a speed, more than the speed of sound. It is said to be moving at :