The stethoscope used by a medical practitioner is based on the phenomenon of multiple reflection of sound waves.
In option 1, multiple reflection of sound waves refers to the process in which sound waves bounce off multiple surfaces before reaching the ears of the practitioner. This phenomenon is utilized in the design of the stethoscope to amplify and transmit the sound of the patient`s internal organs, such as the heart or lungs, to the practitioner.
Option 2, scattering of sound waves, is not the correct answer. Scattering refers to the process in which sound waves are redirected or dispersed by obstacles or irregularities in the medium through which they are traveling. This phenomenon does not play a significant role in the functioning of a stethoscope.
Option 3, refraction of sound waves, also does not apply to the functioning of a stethoscope. Refraction occurs when sound waves change direction or speed as they pass from one medium to another due to the variation in the density of the mediums. This does not occur in the stethoscope.
Therefore, option 1 is the correct answer, as the stethoscope operates based on the multiple reflection of sound waves to help the medical practitioner listen to the internal sounds of a patient`s body.