Question

A tuning fork is excited by striking it with a padded hammer. What would be the nature of the vibrations executed by the prongs as well as the stem of the fork respectively ? (The reference direction is that of the propagation of the sound wave.)

• A. Both vibrate longitudinally
• B. Both vibrate transversely
• C. The prong vibrate longitudinally whereas the stem vibrates transversely
• D. The prong vibrate transversely whereas the stem vibrates longitudinally

Answer 1

The correct option is C The prong vibrate longitudinally whereas the stem vibrates transversely

A wave in which particles of the medium vibrate in the direction of propagation of wave is known as longitudinal wave. A wave in which the particles of the medium vibrate perpendicular to the direction of propagation is known as transverse wave.

When a tuning fork is excited with a padded hammer, the inward and outward motion of the prongs creates a compression and rarefaction of air molecules near the prongs, thus generating a longitudinal wave.

The two waves collide in the middle of prongs and transfer a wave into the stem of the tuning fork. In the stem, the pressure deviations of the wave causes stress along the perpendicular direction of the propagation of wave, thus creating a transverse wave.