एक हियरिंग एड (श्रवण यंत्र) में, उपयोगकर्ता की सहायता के लिए ध्वनि तरंग की निम्नलिखित में से किस विशेषता को मुख्य रूप से संशोधित किया जाता है?

What is the minimum distance a person must stand at from a reflecting surface to hear a distinct echo (assuming speed of sound in air is approximately 344 m/s)?

Sound in the human audible frequency range is commonly referred to as:

Assertion (A): Sound produced from a larger tabla is louder than sound produced from a smaller tabla when struck with equal force. Reason 1 (R1): Loudness increases with an increase in the surface area of the vibrating body. Reason 2 (R2): A larger tabla produces sound of a higher pitch.