Sound waves having frequency lower than 20 Hz are called:
Ultrasonic
Infrasonic
Audible
Echo
Which is the most suitable means of reliable continuous communication between an orbiting satellite and earth:
Mecrowaves
Radio waves
Sound waves
Any light waves
The frequency of silent whistle is:
20,000 Hz – 25000Hz
2000 Hz – 2500Hz
200 KHz – 2000 Hz
25000 KHz
How many tubes or electron guns used in a colour television set:
Two
Four
Five
Three
Sound waves having frequency higher than 20,000 Hz are called:
