Q. Which of the following is/are uses of multiple reflection of sound?

1. Megaphones or loudhailers, horns
2. Stethoscope
3. Optical Fibre

Select the correct answer from the codes given below:
Answer: Only 1 and 2
Notes: The repeated reflection that results in this persistence of sound is called reverberation. Megaphones or loudhailers, horns, musical instruments such as trumpets and shehanais, are all designed to send sound in a particular direction without spreading it in all directions. Stethoscope is a medical instrument used for listening to sounds produced within the body, mainly in the heart or lungs. In stethoscopes the sound of the patient's heartbeat reaches the doctor's ears by multiple reflection of sound.