🎵 Chapter 13: Sound – Multiple Choice Questions
Prepared by Muhammad Tayyab, Subject Specialist Physics, Govt Christian High School Daska. Based on PECTAA 2026 syllabus (National Curriculum 2023).
📖 What's Inside: This section covers Multiple Choice Questions from Chapter 13 Sound including sound production, echo, longitudinal waves, speed of sound in different media, acoustic protection, and audible frequency range. Each MCQ is presented with the correct answer and detailed explanation as per the official PECTAA 2026 Physics curriculum.
📚 Related Resources – Chapter 13: Sound
Sound covers waves, echo, ultrasound, SONAR, pitch, loudness, and acoustics. Includes solved examples and numerical problems.
📖 Multiple Choice Questions & Answers (PECTAA 2026)
13.1 What is required for the production of sound?
✅ Correct Answer: B
Explanation: Sound is a mechanical wave produced by vibrating bodies. It requires a material medium (solid, liquid, or gas) for its propagation and cannot travel through a vacuum.
Explanation: Sound is a mechanical wave produced by vibrating bodies. It requires a material medium (solid, liquid, or gas) for its propagation and cannot travel through a vacuum.
13.2 An echo is produced due to:
✅ Correct Answer: B
Explanation: An echo is simply the repetition of sound caused by the reflection of sound waves from a hard surface or obstacle back to the listener.
Explanation: An echo is simply the repetition of sound caused by the reflection of sound waves from a hard surface or obstacle back to the listener.
13.3 An example of a longitudinal wave is:
✅ Correct Answer: C
Explanation: Sound waves are longitudinal waves because the particles of the medium vibrate back and forth along the same direction in which the wave travels. Light, water, and radio waves are transverse waves.
Explanation: Sound waves are longitudinal waves because the particles of the medium vibrate back and forth along the same direction in which the wave travels. Light, water, and radio waves are transverse waves.
13.4 In which medium does sound travel the fastest?
✅ Correct Answer: C
Explanation: Sound travels 5 times faster in liquids and 15 times faster in solids than in gases.
Explanation: Sound travels 5 times faster in liquids and 15 times faster in solids than in gases.
13.5 What is the approximate speed of sound in air?
✅ Correct Answer: B
Explanation: The speed of sound in air at standard room temperature and pressure is approximately \( 330-343 \, \text{ms}^{-1} \).
Explanation: The speed of sound in air at standard room temperature and pressure is approximately \( 330-343 \, \text{ms}^{-1} \).
13.6 Why is acoustic protection important in building design?
✅ Correct Answer: B
Explanation: Acoustic protection or insulation uses soft, porous materials to absorb unwanted sound waves, which minimizes reflections (echoes) and improves clarity inside a building.
Explanation: Acoustic protection or insulation uses soft, porous materials to absorb unwanted sound waves, which minimizes reflections (echoes) and improves clarity inside a building.
13.7 For a normal person, the audible frequency range for sound waves lies between:
✅ Correct Answer: B
Explanation: The standard audible frequency range for a healthy human ear is between 20 Hz and 20,000 Hz (20 kHz). Frequencies below or above this range are inaudible.
Explanation: The standard audible frequency range for a healthy human ear is between 20 Hz and 20,000 Hz (20 kHz). Frequencies below or above this range are inaudible.
🔑 Answer Key with Explanations
13.1 Correct Answer: (B) Vibrations of a medium
Sound is a mechanical wave produced by vibrating bodies. It requires a material medium (solid, liquid, or gas) for its propagation and cannot travel through a vacuum.
13.2 Correct Answer: (B) reflection of sound waves
An echo is simply the repetition of sound caused by the reflection of sound waves from a hard surface or obstacle back to the listener.
13.3 Correct Answer: (C) sound wave
Sound waves are longitudinal waves because the particles of the medium vibrate back and forth along the same direction in which the wave travels. Light, water, and radio waves are transverse waves.
13.4 Correct Answer: (C) Solids
Sound travels 5 times faster in liquids and 15 times faster in solids than in gases.
13.5 Correct Answer: (B) \( 330-350 \, \text{ms}^{-1} \)
The speed of sound in air at standard room temperature and pressure is approximately \( 330-343 \, \text{ms}^{-1} \).
13.6 Correct Answer: (B) To reduce echo and improve sound quality
Acoustic protection or insulation uses soft, porous materials to absorb unwanted sound waves, which minimizes reflections (echoes) and improves clarity inside a building.
13.7 Correct Answer: (B) 20 Hz and 20 kHz
The standard audible frequency range for a healthy human ear is between 20 Hz and 20,000 Hz (20 kHz). Frequencies below or above this range are inaudible.
📐 Key Formulas – Sound
Wave Equation: \( v = f\lambda \)
Time Period: \( T = \frac{1}{f} \)
SONAR / Echo Distance: \( d = \frac{v \times t}{2} \)
💡 Exam Tip:
For MCQs, focus on key definitions, formulas, and conceptual understanding. Pay attention to the distinction between longitudinal and transverse waves, speed of sound in different media, and the audible frequency range. These MCQs follow the PECTAA 2026 pattern and are prepared by Subject Specialist Muhammad Tayyab.
Unit 10Thermal Physics
Unit 11Transfer of Thermal Energy
Unit 12Waves
Unit 13✨ Sound
Unit 14Light
Unit 15Electrostatics
Unit 16Electricity
Unit 17Electromagnetism
Unit 18Electromagnetic Induction & EM Waves
Unit 19Electronics
Unit 20Atomic and Nuclear Physics
Unit 21Space and Environment
📖 Complete syllabus coverage for Class 10 Physics (PECTAA 2026) – Units 10 to 21
Created by Hira Science Academy | Aligned with PECTAA 2026 Syllabus