Question

The ratio of the velocity of body and velocity of sound is known as
(A) Laplace number
(B) Positive number
(C) Stable number
(D) Mach number

Answer 1

We know that Mach number is defined as the ratio of the velocity of body and velocity of sound, it is represented as (Ma). $Ma = \dfrac{{{V_{body}}}}{{{V_{ms}}}}$ here, ${V_{ms}}$ is the velocity of sound in the medium.

Complete step by step answer:
We know that Laplace number is given by the ratio of the surface tension to the momentum-transport inside a fluid. It is dimensionless. The Laplace number is also known as the Suratman number. So, option A is wrong.
In option B we have a positive number, we know that a positive number is a real number which is greater than 0. But all positive numbers do not give us the value of the ratio of the velocity of the body and velocity of sound. So, option B is wrong.
In option C we have a stable number. We know that A stable number is a number in which each digit occurs the same number of times for example 2244, 5566, etc. are stable numbers. Not all stable numbers need to give us the ratio of the velocity of the body and velocity of sound so option C is wrong.
In option D we have the Mach number. We know that Mach number is defined as the ratio of the velocity of the body to the velocity of sound, so option D is correct. It is represented as $Ma = \dfrac{{{V_{body}}}}{{{V_{ms}}}}$. Here, ${V_{body}}$ is the velocity of the body and ${V_{ms}}$ is the velocity of the sound in the medium.

Therefore, option D is correct.

Note:
One can confuse between option A and option D and tick option A as their response nut please Note: that Laplace number is the ratio of the surface tension to the momentum-transport inside fluid and this Mach number will give us the ratio of the velocity of the body to the velocity of sound.