Duration of second hea sound is: (A) 0.12 Sec, (B) 0.1 Sec, (C) 0.15 Sec, (D) 0.2 Sec
Answer is A. The second sound lasts about 0.12 s, with a frequency of 50 Hz. It is loud and sharp when the diastolic pressure in the aoa or pulmonary aery is elevated, causing the respective valves to shut briskly at the end of systole.Ref: Ganong&;s Review of medical physiology 25th edition. Page: 542