Sound

Consider the following statements about ultrasonic waves: 1. They can destroy insects. 2. They can clean clothes by removing dust. 3. They can be used to treat diseases. 4. They can control automatic doors. Of the above statements

Ultrasonics are sound waves of frequency :

What is the audible range (hearing range) of humans?

What is/are not true among the following? 1. Audible range of sound for human beings is approximately 20 Hz to 20 kHz. 2. Sound waves with frequencies higher than 10 kHz are called ultrasound. 3. In earthquake, ultrasounds are produced before the main shock waves.

A biotechnological use in which ultrasonic sound is used :

Which of the following rays/waves are used to know the growth of foetus in the womb?

Bats can fly during dark nights and also prey. This is because:

Consider the following statements: 1. The heart vibrates at infrasonic. 2. The speed of sound is more in gas than in liquid and solid. 3. Mach number is used to describe the speed of sound. 4. Ultrasonic sound has frequency more than 20,000 Hz. Of these statements :

In Stethoscope, the sound of the patient’s heartbeat reaches the doctor’s ears by :

Which one of the following is the effect of the flight of supersonic jet?