1 Mach number means-

  1. speed of sound = speed of object
  2. velocity of light = speed of sound
  3. speed of sound = 1 km/h
  4. speed of sound = 10m/s

Answer (Detailed Solution Below)

Option 1 : speed of sound = speed of object
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Detailed Solution

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CONCEPT:

  • Mach number: The ratio of the speed of an object to the speed of sound is called the Mach number.

\(Mach~number = {speed ~ of~object \over speed ~of ~sound}\)

EXPLANATION:

If Mach number = 1

\(Mach~number = 1={speed ~ of~object \over speed ~of ~sound}\)

speed of object = speed of sound

This speed of an object (Mach number = 1) is also known as transonic speed.

So the correct answer is option 1.

Additional Information

Mach numbers < 1 ⇔ Subsonic flow;

Mach numbers > 1  Supersonic flow.

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