Question

Ultrasonic wave is a :

• A. Transverse wave
• B. Longitudinal wave
• C. Progressive wave
• D. Stationary wave

Hint:

Sound waves (including audible, infrasonic, and {ultrasonic}) are always {longitudinal waves}. The particles of the medium vibrate back and forth in the same direction the wave is traveling.
{Light waves} (and other electromagnetic waves) are {transverse waves}. The oscillations are perpendicular to the direction the wave is traveling. "Progressive" means it travels. "Stationary" means it doesn't appear to travel. These are different classifications.

Answer 1

The Correct Option is B

Concept: Waves can be classified based on the direction of particle oscillation relative to the direction of wave propagation. Ultrasonic waves are sound waves with frequencies higher than the upper audible limit of human hearing (typically above 20 kHz). Step 1: Understanding different types of waves based on particle motion
Longitudinal Wave: In a longitudinal wave, the particles of the medium oscillate (vibrate) parallel to the direction in which the wave travels. These waves consist of compressions (regions of high density/pressure) and rarefactions (regions of low density/pressure). Sound waves (including audible sound, infrasound, and ultrasound) are examples of longitudinal waves.
Transverse Wave: In a transverse wave, the particles of the medium oscillate perpendicular to the direction in which the wave travels. These waves consist of crests and troughs. Light and other electromagnetic waves are examples of transverse waves. Waves on a string are also transverse. Step 2: Understanding other wave classifications given in options
Progressive Wave (or Traveling Wave): A wave that transfers energy from one point to another as it travels through a medium or vacuum. Both longitudinal and transverse waves can be progressive.
Stationary Wave (or Standing Wave): A wave that oscillates in time but whose peak amplitude profile does not move in space. It is formed by the superposition of two waves (often an incident wave and its reflection) traveling in opposite directions. Both longitudinal and transverse waves can form stationary waves. These classifications (Progressive/Stationary) describe the wave's behavior in terms of energy transfer and spatial movement, not the direction of particle oscillation. Step 3: Classifying Ultrasonic Waves Ultrasonic waves are essentially sound waves, just with frequencies too high for humans to hear. Sound waves are longitudinal waves. They propagate through a medium by causing compressions and rarefactions of the particles in that medium. Ultrasonic waves are also progressive waves as they travel and transfer energy. They can also form stationary waves under appropriate conditions. However, the question "Ultrasonic wave is a :" is primarily asking for its fundamental nature regarding particle motion. Step 4: Choosing the most appropriate classification The most fundamental classification based on the nature of particle oscillation is whether it's longitudinal or transverse. Since ultrasonic waves are a type of sound wave, they are longitudinal waves. Options (3) and (4) describe other aspects of wave behavior that can apply to both longitudinal and transverse waves. Option (1) is incorrect as sound waves are not transverse.