Answer: Ultrasound.
- A Infrasound
- B Audible sound
- C Ultrasound
- D Electromagnetic waves
Correct answer: C. Ultrasound
Explanation: SONAR (Sound Navigation And Ranging) uses ultrasonic waves to detect objects underwater.
A standing wave forms from two identical waves travelling in opposite directions and interfering; nodes (always zero displacement) and antinodes (maximum displacement) stay fixed in place, unlike a travelling wave where the whole pattern moves.
Concept context
Wave types, superposition, standing waves, Doppler effect, and sound intensity.