Doctors use __________ to hear the sound of heart

Q. Shyam is a doctor. He decided to start a clinic in his home town. From the given list of devices, choose the decvices that would serve him well in his new clinic.

(A) Telescope
(B) Stethoscope
(C) Sphygmomanometer
(D) Odometer
(E) Barometer
(F) Electrocardiogram
(G) Ultrasound scanner

Q. Doctors use a stethoscope to:

Q. Doctors use stethoscope to hear the sounds produced during each cardiac cycle. The second sound in heard when :

Q. You must have seen the doctor checking the sounds produced in the chest of a patient using medical instrument called stethoscope. On what principle does this stethoscope works?