Question

Assertion :Statement-1 : Echo is produced when sound is incident on hard and polished surface. Reason: Statement-2 : Sound energy can be totally reflected by objects with soft and loose texture.

• A. Both Statements-1 and 2 are true and Statement-2 is the correct explanation of Statement-1.
• B. Both Statements-1 and 2 are true but Statement-2 is not the correct explanation of Statement-1.
• C. Statement-1 is true and Statement-2 is false.
• D. Both Statements-1 and 2 are false.

Answer 1

The correct option is C Statement-1 is true and Statement-2 is false.

Answer is C.

Echoes are created by sound waves being reflected off of a large obstacle. Conditions have to be just right for the echo to be heard as a separate sound.The size of the object the sound wave is being reflected upon must be larger than the sound wave itself.It must be hard and polished surface. Echoes must also be loud enough or intense enough to be heard, and the original sound must be very short.
When a sound wave meets an obstacle, some of the sound is reflected back from the front surface and some of the sound passes into the obstacle material, where it is absorbed or transmitted through the material. Reflection and absorption are dependent on the wavelength of the sound. The percentage of the sound transmitted through an obstacle depends on how much sound is reflected and how much is absorbed.
Therefore, the statement 1 is true and the statement 2 is false.