Exposure to very loud sounds above which of the following approximate sound levels (measured in decibels) is most likely to cause immediate damage to human hearing?

Introduction / Context:
Noise pollution and loud sounds can affect human health, especially the sensitive structures of the inner ear. Hearing loss can occur gradually from moderate noise or suddenly from extremely loud noise. In general knowledge and health education, a particular sound level in decibels is often cited as the threshold where immediate risk of hearing damage becomes significant. This question asks at what approximate sound level such damage is likely.

Given Data / Assumptions:

• Sound intensity is measured in decibels (dB).
• The options are 70 dB, 80 dB, 100 dB, 120 dB, and 140 dB.
• We focus on the level above which loud sounds can cause pain and potential sudden damage, not just long term risk.
• We assume typical textbook values used for awareness of noise hazards.

Concept / Approach:
Normal conversation is around 60 to 65 dB. Continuous exposure above about 80 to 85 dB can cause gradual hearing loss over time. However, sounds at or above about 120 dB are close to the threshold of pain and can cause immediate damage to the ear, especially if exposure is prolonged or very sudden. This is why many GK sources state that sound levels above 120 dB are harmful and can damage hearing. Levels around 140 dB, such as a jet engine at close range, are even more dangerous, but the standard teaching threshold for initial damage is 120 dB.

Step-by-Step Solution:
Step 1: Recall typical sound levels: whisper around 30 dB, conversation around 60 dB, busy traffic around 80 to 90 dB.Step 2: Understand that long term exposure to 80 to 90 dB may cause gradual hearing loss but is not usually cited as the sudden damage threshold.Step 3: Remember that sounds around 120 dB are described as extremely loud and painful to the ears and can cause damage.Step 4: 140 dB is even more dangerous, but standard GK questions often use 120 dB as the reference level beyond which sound becomes harmful.Step 5: Therefore, choose 120 decibels as the answer.

Verification / Alternative check:
Health and safety guidelines often place the threshold of pain for human ears at around 120 to 130 dB and warn that exposure to such levels, even for short periods, can damage hearing. Occupational regulations may set stricter limits for continuous exposure, but for general awareness, 120 dB is often highlighted as the critical level above which sound can immediately harm the ear. This supports selecting 120 dB in typical multiple choice questions.

Why Other Options Are Wrong:
70 dB is only slightly above conversation level and is not usually harmful.80 dB can be harmful with prolonged exposure over many hours or years but is not the standard immediate damage threshold in GK questions.100 dB is very loud and potentially harmful, yet most textbook illustrations reserve the term threshold of pain or sure damage for about 120 dB.140 dB is extremely dangerous and certainly damaging, but the question asks for the approximate level commonly cited, which is 120 dB.

Common Pitfalls:
Some students may select 80 or 100 dB because they know that long term exposure to lower noise levels can still damage hearing. Others may choose 140 dB because it sounds extremely loud. To avoid confusion, remember that in school level general knowledge, 120 dB is widely used as the standard cut off for immediately dangerous noise causing hearing damage and pain.

Final Answer:
The correct answer is 120 decibels.