Question

For the production of an echo, size and nature of obstacle should be:

• A. quite small, rigid
• B. quite small, soft
• C. quite large, rigid
• D. quite large, soft

Answer 1

The correct option is C quite large, rigid

For the production of an echo, the reflecting surface or the obstacle should be rigid such as building, hill, cliff.
Echo can be produced if the size of the obstacle reflecting the sound is quite large.