Consider the following statements about the propagation of sound in a slinky: 1. It can demonstrate longitudinal waves. 2. The regions where coils are closer are called rarefactions. 3. The regions where coils are further apart are called compressions. Which of the statements given above is/are correct?

Correct Option The correct option is (a). Explanation Sound waves are mechanical waves that propagate through a medium via the oscillation of particles. A slinky (a coiled spring) is a standard physical model used to demonstrate wave mechanics. It can illustrate both transverse waves (by moving the end side-to-side) and longitudinal waves (by moving the end back-and-forth), the latter being the mode of propagation for sound in fluids. Statement-wise Analysis - Statement 1 is Correct: A slinky can demonstrate longitudinal waves. When the coils are pushed and pulled along the length of the spring, the disturbance moves parallel to the direction of the coils' oscillation. This mirrors the propagation of sound waves in air. - Statement 2 is Incorrect: In a longitudinal wave, the regions where the particles of the medium (or coils of the slinky) are crowded close together are regions of high density and pressure. These are technically termed compressions, not rarefactions. - Statement 3 is Incorrect: The regions where the particles of the medium (or coils of the slinky) are spread further apart are regions of low density and pressure. These are technically termed rarefactions, not compressions. Key Takeaway: Sound propagates as a longitudinal wave characterized by alternating regions of high pressure called compressions and low pressure called rarefactions.

Consider the following statements about the propagation of sound in a slinky: 1.… - NCERT Class 9 Science MCQ

NCERT Class 9 Science — Chapter 5: Sound

mcqeasy

Consider the following statements about the propagation of sound in a slinky:

It can demonstrate longitudinal waves.
The regions where coils are closer are called rarefactions.
The regions where coils are further apart are called compressions.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 9 · Page 3

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (a).

Explanation

Sound waves are mechanical waves that propagate through a medium via the oscillation of particles. A slinky (a coiled spring) is a standard physical model used to demonstrate wave mechanics. It can illustrate both transverse waves (by moving the end side-to-side) and longitudinal waves (by moving the end back-and-forth), the latter being the mode of propagation for sound in fluids.

Statement-wise Analysis

Statement 1 is Correct: A slinky can demonstrate longitudinal waves. When the coils are pushed and pulled along the length of the spring, the disturbance moves parallel to the direction of the coils' oscillation. This mirrors the propagation of sound waves in air.
Statement 2 is Incorrect: In a longitudinal wave, the regions where the particles of the medium (or coils of the slinky) are crowded close together are regions of high density and pressure. These are technically termed compressions, not rarefactions.
Statement 3 is Incorrect: The regions where the particles of the medium (or coils of the slinky) are spread further apart are regions of low density and pressure. These are technically termed rarefactions, not compressions.

Key Takeaway: Sound propagates as a longitudinal wave characterized by alternating regions of high pressure called compressions and low pressure called rarefactions.

Your note

More from Chapter 5: Sound

Consider the following statements about the 'Hearing Aid': 1. It is a battery-operated electronic device. 2. The microphone converts electrical signals into sound. 3. The speaker converts sound waves into electrical signals. Which of the statements given above is/are correct?

medium

What is the primary purpose of designing curved ceilings in concert halls and cinema halls?

easy

"A violin and a flute may be played at the same time... but the sounds we receive are different." This difference is primarily due to which characteristic of sound?

medium

With reference to the audible range of sound, consider the following statements: 1. The audible range for an average human is 200 Hz to 200,000 Hz. 2. Sounds with frequencies below 20 Hz are called infrasound. 3. Rhinoceroses communicate using infrasound. Which of the statements given above are correct?

medium

Ordinary sound waves are unsuitable for detecting flaws in metal blocks primarily because:

hard

Keep practising Chapter 5: Sound

Work through every question from this NCERT chapter.

Browse all NCERT Class 9 Science chapters