Rupture of an ear drum may occur at the noise level above :
**Core Concept**
The question is testing the level of sound intensity that can cause damage to the ear drum, specifically the threshold at which rupture occurs. This is related to the concept of sound-induced trauma and the mechanical properties of the ear drum.
**Why the Correct Answer is Right**
Sound-induced rupture of the ear drum is a well-known phenomenon, particularly in the context of loud noises or explosions. The ear drum is a thin membrane that separates the middle ear from the outer ear. When sound waves reach a certain intensity, they can cause the ear drum to vibrate violently, leading to a rupture. The critical level of sound intensity that can cause rupture is typically above 140 decibels (dB). This is because sound waves above 140 dB can produce forces strong enough to cause the ear drum to tear.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because the sound level below 100 dB is typically not sufficient to cause rupture of the ear drum.
**Option B:** Incorrect because the sound level around 120 dB may cause temporary threshold shift or discomfort, but it is unlikely to cause rupture.
**Option C:** Incorrect because the sound level above 160 dB is more likely to cause permanent damage to the ear drum, but the exact threshold for rupture is typically considered to be around 140 dB.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that prolonged exposure to sound levels above 85 dB can cause permanent hearing loss. The National Institute for Occupational Safety and Health (NIOSH) recommends that workers avoid exposure to sound levels above 85 dB for more than 8 hours a day.
**Correct Answer: C. 160 dB**