Continuous exposure to very loud sounds can damage the human ear. Damage to hearing is likely to occur when sound intensity exceeds approximately how many decibels?

Introduction / Context:
The decibel is a unit used to measure the intensity or loudness of sound. Prolonged exposure to high decibel levels can damage delicate structures in the inner ear and lead to hearing loss. This question asks about the approximate decibel level beyond which sound can cause damage to hearing, especially in the context of very loud noises.

Given Data / Assumptions:

• We are concerned with loud sounds and potential damage to hearing.
• Typical conversational sound levels are much lower than those in the options.
• The options range from moderately loud to extremely loud decibel values.

Concept / Approach:
Sound around 60 decibels corresponds roughly to normal conversation. Levels around 80 to 90 decibels can be harmful with long term exposure. Extremely loud sounds, such as jet engines or loud rock concerts, often reach 110 to 120 decibels or more. At around 120 decibels, sound is often described as the threshold of pain, and short term exposure can start to damage the ear. General knowledge textbooks often use 120 decibels as the reference value beyond which damage is likely.

Step-by-Step Solution:
Step 1: Compare the options with typical sound level examples. Conversation is about 60 decibels, traffic noise may be around 70 to 80, while very loud music or engines can exceed 100. Step 2: Recognise that damage to hearing is strongly associated with the highest levels in the list, especially near the threshold of pain. Step 3: General knowledge references often cite 120 decibels as a level where even brief exposure can cause injury. Step 4: Select 120 decibels as the answer that best matches the description of damaging loudness.

Verification / Alternative check:
Hearing safety guidelines warn that sounds above about 85 decibels can cause damage if exposure is prolonged, and that very loud sounds near 120 decibels can cause immediate harm. School level questions tend to choose a single high value for memorisation, and 120 decibels is widely used in exam oriented material to indicate a dangerous level that can damage hearing.

Why Other Options Are Wrong:

• Option A (70 decibels): This corresponds to fairly loud traffic or a noisy room and is not usually associated with immediate severe damage, although long term exposure can still be harmful.
• Option B (80 decibels): This level is potentially harmful with prolonged exposure but is not the typical textbook threshold for immediate damage.
• Option C (100 decibels): This is very loud and can be harmful, but general knowledge questions commonly emphasise 120 decibels as the classic damage threshold.

Common Pitfalls:
Students may think that any loud sound above everyday levels immediately causes damage. While this can be true for very high intensities, risk depends on both intensity and duration. For exam purposes, it is important to remember the reference number used in textbooks, which is around 120 decibels as the level beyond which damage to hearing is likely.

Final Answer:
Damage to hearing is likely when sound intensity exceeds about 120 decibels.