Unit 12: Waves – Multiple Choice Questions (MCQs)

Class 10 Physics Notes (New 2026) | Unit 12 – MCQs | PECTAA Syllabus

✅ Chapter 12: Waves – 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 the official PECTAA 2026 curriculum: longitudinal & transverse waves, wavefront, amplitude (energy), refraction, diffraction, tsunami wave behavior, and more. Each question includes four options and a detailed explanation for the correct answer.

⬇️ Download PDF (MCQs)

📚 Related Resources – Chapter 12: Waves

📝 Short Questions 📋 Exercise Short Qs ✏️ Constructed Response 📖 Long Questions 📐 Numerical Problems

Practice MCQs to test your understanding of wave phenomena for board exams.

📑 Quick Jump to MCQs

Q12.1 Q12.2 Q12.3 Q12.4 Q12.5 Q12.6 Q12.7 Q12.8

📖 Multiple Choice Questions & Answers (PECTAA 2026)

12.1 The direction of vibration in a longitudinal wave is:
A. at right angles to the wave direction B. in circular motion C. opposite to the wave direction D. in the same direction as the wave travels ✓ Correct
✅ Correct Answer: D. in the same direction as the wave travels
Explanation: In a longitudinal wave, particles vibrate parallel to the direction of wave travel (e.g., sound waves). The oscillations are along the propagation axis.
12.2 Which part of a transverse wave carries the lowest point?
A. Crest B. Compression C. Rarefaction D. Trough ✓ Correct
✅ Correct Answer: D. Trough
Explanation: In a transverse wave, the trough is the lowest point (minimum displacement), while the crest is the highest point.
12.3 Which of the following wave types requires a medium to travel?
A. X-rays B. Light waves C. Radiowaves D. Sound waves ✓ Correct
✅ Correct Answer: D. Sound waves
Explanation: Sound waves are mechanical waves and require a medium (solid, liquid, or gas) to propagate. X-rays, light, and radiowaves are electromagnetic waves that can travel through vacuum.
12.4 The property of a wave which indicates how much energy it carries is:
A. crest B. amplitude ✓ Correct C. wavelength D. speed
✅ Correct Answer: B. amplitude
Explanation: Amplitude is a measure of the energy carried by a wave. Larger amplitude means more energy. For example, loud sound has high amplitude, bright light has large electric field amplitude.
12.5 A wave front is:
A. the distance between two crests B. a region of high pressure in a wave C. a line joining points that vibrate in phase ✓ Correct D. the outer edge of a wave medium
✅ Correct Answer: C. a line joining points that vibrate in phase
Explanation: A wave front connects points on adjacent waves that are at the same stage of vibration (in phase). Examples: crests or troughs form wavefronts.
12.6 The wave phenomenon which occurs when waves change direction due to a change in speed is:
A. diffraction B. reflection C. absorption D. refraction ✓ Correct
✅ Correct Answer: D. refraction
Explanation: Refraction is the change in direction of a wave as it changes speed when moving from one medium to another. Example: bending of light in water.
12.7 What happens to wave speed and wavelength when a tsunami approaches shallow water?
A. Speed increases, wavelength increases B. Speed decreases, wavelength shortens ✓ Correct C. Speed remains the same, wavelength shortens D. Speed increases, wavelength stays constant
✅ Correct Answer: B. Speed decreases, wavelength shortens
Explanation: In shallow water, a tsunami's speed decreases due to friction with the seabed, causing its wavelength to shorten (frequency remains constant, as per v = fλ).
12.8 Which wave behaviour explains how sound is heard around a corner?
A. Reflection B. Refraction C. Interference D. Diffraction ✓ Correct
✅ Correct Answer: D. Diffraction
Explanation: Diffraction is the bending of waves around obstacles or edges, allowing sound to be heard around a corner. It occurs when wave encounters an obstacle whose size is comparable to wavelength.

🌊 Key Wave Concepts Covered

Wave Speed: \( v = f \lambda \)
Energy ∝ (Amplitude)²

💡 Exam Tip:

For MCQs on waves: Remember longitudinal vs transverse particle motion. Amplitude determines energy. Refraction involves speed change and bending. Diffraction explains bending around edges. For tsunamis in shallow water: speed ↓, wavelength ↓, frequency constant.

📖 Complete syllabus coverage for Class 10 Physics (PECTAA 2026) – Units 10 to 21

Created by Hira Science Academy | Aligned with PECTAA 2026 Syllabus

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