Normal voice heard from 1 meter, intensity of sound reaching ear is -: (A) 20 dB, (B) 40 dB, (C) 60 dB, (D) 80 dB
Answer is C. Normal conversation produces 60-70 dB. Whisper 20-30 dB. Mechanical damage at 150-160 dB REF. PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE 22nd EDITION. PAGE NO - 688