Chapter 15.1, Problem 11SSC

(a)

To determine

To compare:The echoes from large and small insects if they were at the same distance from the bat.

Explanation of Solution

Introduction:

Bats use Doppler Effect to detect and catch flying insects.

The echo from an object depends on the distance from the object and its depth. Hence, the size of the object matters.Although the two insects are at the same distance from the bat, the reflected frequency depends on the size of the object.

Therefore, the echo from the large insect has high-reflected frequency and so is louder; whereas, the echo from the small object has reflected frequency lower than that of the large insect.

Conclusion:

The echo from the large insect has high-reflected frequency and so is louder; whereas, the echo from the small object has reflected frequency lower than that of the large insect.

(b)

To determine

To differentiate:Echoes from an insect flying towards the bat and that of an insect flying away from the bat.

Explanation of Solution

Introduction:

The echo from an object depends on the distance from the object and its depth.

Bats use Doppler Effect to detect and catch flying insects.

The echo from an object depends on the distance from the object and its depth.

When the insect is moving towards the bat, the echo is louder as the distances decreases. When the insect is flying away from the bat, the distance increases between them and the echo becomes fainter with distance.

Conclusion:

When the insect is moving towards the bat, the echo is louder, whereas, when the insect is flying away from the bat, the echo becomes fainter with distance.