Advertisements
Advertisements
Question
How does a bat make use of ultrasonics waves to find its way?
Advertisements
Solution
Use of ultrasonics by bats : Bats have no eyes. But they easily move about without colliding with any object (or obstacle). The reason is that they produce ultrasonic sound as they fly. When this ultrasonic sound comes back after reflection from any object (or obstacle) in their way, they hear it and thus they detect the presence of the object (or obstacle).
APPEARS IN
RELATED QUESTIONS
Fill in the blank.
________ produces a sensation in ears.
| Column A | Column B |
| (a) Vibrations cause | (1) absorb sound |
| (b) A shriller sound is | (2) second |
| (c) Unit of frequency | (3) sound |
| (d) Unit of time period | (4) of high pitch |
| (e) Curtains | (5) hertz |
In an experiment, Anhad studies sound waves. He sets up a loudspeaker to produce sound as shown below :
Anhad adjusts the signal to the loudspeaker to give a sound of frequency 200 Hz.
(a) What happens to the air in-between Anhad and the loudspeaker ?
(b) Explain how Anhad receives sound in both ears.
Draw a displacement-distance graph of a wave and mark on it, the amplitude of wave by the letter 'a' and wavelength of wave by the letter λ.
The heart of a man beats 75 times a minute. What is its (a) frequency and (b) time period?
A cannon is fired at A (see diagram). An observer at B hears two sounds. The first sound is heard after 1 second and the second 3s after the observer sees the flash. (Velocity of sound = 340 ms−1)
(i) Why does the observer see the flash before he hears the sound?
(ii) Calculate the distance x between the observer and the wall.
The distance between three consecutive crests of wave is 60 cm. If the waves are produced at the rate of 180/ min, calculate:
- wavelength
- time period
- wave velocity.
A musical instrument is producing continuous note. This note cannot be heard by a person having a normal hearing range. This note must then be passing through ______.
Two observers are stationed in two boats 4.5 km apart. A sound signal sent by one, under water, reaches the other after 3 seconds. What is the speed of sound in the water?
