Question

Three different vibrating bodies produce three types of sounds X, Y and Z.
Sounds X and Y cannot be heard by a man having normal range of hearing but sound Z can be heard easily.
The sound X is used in for monitoring nuclear reactor. The sound similar to that which is produced during an earthquake before the mainshock wave is generated.

What type of sounds are (i) X (ii) Y, and (iii) Z?

• A. X - infrasound, Y - ultrasound, Z - audible sound
• B. X - audible sound, Y - infrasound, Z - ultrasound
• C. X - ultrasound, Y - infrasound, Z - audible sound
• D. X - infrasound, Y - audible sound, Z - audible sound

Answer 1

The correct option is C X - ultrasound, Y - infrasound, Z - audible sound

Ultrasound is used to see what is happening in a nuclear reactor. Ultrasounds and infrasounds are not audible to man. Ultrasound have frequency more than 20 kHz.
Infrasound have frequency below 20Hz.