Every Book Back multiple-choice question from Acoustics (10th Standard Science, Samacheer Kalvi) — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
When a sound wave travels through air, the air particles
- A. vibrate along the direction of the wave motionCorrect
- B. vibrate but not in any fixed direction
- C. vibrate perpendicular to the direction of the wave motion
- D. do not vibrate
Explanation. Sound waves are longitudinal waves. When they travel through air, the air particles vibrate back and forth along the direction of wave propagation, creating regions of compression and rarefaction.
Q2
Velocity of sound in a gaseous medium is 330 ms–1. If the pressure is increased by 4 times without causing a change in the temperature, the velocity of sound in the gas is
- A. 330 ms–1Correct
- B. 660 ms–1
- C. 156 ms–1
- D. 990 ms–1
Explanation. At a constant temperature, the velocity of sound in a gas is independent of changes in pressure. Therefore, even if pressure increases by four times, the velocity remains unchanged at 330 ms–1.
Q3
The frequency, which is audible to the human ear is
- A. 50 kHz
- B. 20 kHzCorrect
- C. 15000 kHz
- D. 10000 kHz
Explanation. The audible frequency range for the human ear is between 20 Hz and 20,000 Hz (which is 20 kHz). Therefore, 20 kHz is within the audible range, while the other options represent ultrasonic frequencies.
Q4
The velocity of sound in air at a particular temperature is 330 ms–1. What will be its value when temperature is doubled and the pressure is halved?
- A. 330 ms–1
- B. 165 ms–1
- C. 330 × √2 ms–1Correct
- D. 320 / √2 ms–1
Explanation. The velocity of sound in a gas is independent of pressure but directly proportional to the square root of absolute temperature. Doubling the temperature increases the velocity by a factor of root two, resulting in 330 × √2 ms–1.
Q5
If a sound wave travels with a frequency of 1.25 × 10⁴ Hz at 344 ms–1, the wavelength will be
- A. 27.52 m
- B. 275.2 m
- C. 0.02752 mCorrect
- D. 2.752 m
Explanation. Using the wave equation velocity equals frequency times wavelength, we calculate wavelength by dividing the velocity of 344 ms–1 by the frequency of 1.25 × 10⁴ Hz, which gives 0.02752 meters.
Q6
The sound waves are reflected from an obstacle into the same medium from which they were incident. Which of the following changes?
- A. speed
- B. frequency
- C. wavelength
- D. none of theseCorrect
Explanation. When sound waves are reflected back into the same medium, their speed, frequency, and wavelength remain unchanged. Speed depends on the medium, frequency depends on the source, and wavelength remains constant as a result.
Q7
Velocity of sound in the atmosphere of a planet is 500 ms–1. The minimum distance between the sources of sound and the obstacle to hear the echo, should be
- A. 17 m
- B. 20 m
- C. 25 mCorrect
- D. 50 m
Explanation. To hear a distinct echo, the minimum time interval between original and reflected sounds is 0.1 seconds. With a velocity of 500 ms–1, the sound travels 50 meters in this time, requiring an obstacle distance of 25 meters.
About these Acoustics questions
These are the Book Back multiple-choice questions for Acoustics from the Tamil Nadu State Board (Samacheer Kalvi) 10th Standard Science syllabus. Each question shows the correct option and an original, step-by-step explanation so you understand the method, not just the answer. Use the answer key above to jump to any question, then take the practice test to check yourself under exam-like conditions.
Frequently asked questions
How many MCQs are there in Acoustics?
This chapter has 7 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.
Are these 10th Standard Science MCQs free to practise online?
Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.
Where can I find the Acoustics book-back answers?
The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.
