Sound Test - 65...

A sound wave whose frequency is 220 Hz has a speed of $$440ms^{-1}$$  in a given medium.  The wavelength of the sound is: 

Which of the following option is incorrect?

Sound waves having the following frequency are audible to human beings:

The device which is not based on the reflection of sound is 

An echo is heard only, if the original sound after reflection reaches the ear in

Ultrasonic signal sent from $$SONAR$$ returns to it after reflection from a rock after a lapse of $$1\, s$$. If the velocity of ultrasound in water is $$1600\, m/s$$, the depth of the rock in water is 

The frequency of a rod is $$200\ Hz$$. If the velocity of sound in air is $$340\ ms^{ -1 }$$, the wavelength of the sound produced is 

The speed of sound in air is $$340\ m/s$$, while in water is $$1445\ m/s$$. If the wavelength of sound in water is $$8.5\ cm$$, the wavelength of sound in air is

An astronaut can not hear his companion's sound at the surface of moon because:

When a tuning fork vibrates, the waves produced in the stem are: