What angle do longitudinal waves make during their propagation?

طولانی لہریں اپنے پھیلاؤ کے دوران کون سا زاویہ بناتی ہیں؟

0 degrees

45 degrees

90 degrees

None of these

In longitudinal waves, particle displacement is parallel to the direction of wave propagation, making an angle of 0 degrees.

Examples include sound waves in air.