Question

wht vibrates the ear drum¿

Answer 1

Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum. The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear. These bones are called the malleus, incus, and stapes.

Answer 2

When a pressure wave reaches the ear, a series of high and low pressure regions impinge upon the eardrum. The arrival of a compression or high pressure region pushes the eardrum inward; the arrival of a low pressure regions serves to pull the eardrum outward. The continuous arrival of high and low pressure regions sets the eardrum into vibrational motion

Since the eardrum is set into vibration by the incoming pressure wave, the vibrations occur at the same frequency as the pressure wave