Please give me a large information about Ultrasonic interferometer (minimum in 3 to 4 paragraphs).

3 years ago


Answers : (1)


                                                 Ultrasonic Interferometer


  • To calculate the velocity of ultrasonic sound through different liquid media.

  • To calculate the adiabatic compressibility of the given liquid.


Ultrasonic interferometer, sample liquids, high frequency generator etc.


Ultrasonic interferometer is a simple device which yields accurate and consistent data, from which one can determine the velocity of ultrasonic sound in a liquid medium.


Ultrasonic sound refers to sound pressure with a frequency greater than the human audible range (20Hz to 20 KHz). When an ultrasonic wave propagates through a medium, the molecules in that medium vibrate over very short distance in a direction parallel to the longitudinal wave. During this vibration, momentum is transferred among molecules. This causes the wave to pass through the medium.




Generation of ultrasound:

Ultrasonic can be produced by different methods. The most common methods include:

  1.  Mechanical  method:       In this, ultrasonic frequencies up to 100 KHz are produced. But this method is rarely used due to its limited frequency range.

  2. Piezoelectric generator:    This is the most common method used for the production of ultrasound. When mechanical pressure is applied to opposite faces of certain crystals which are cut suitably, it get contracted and expanded. i.e., a rapid alternating electric field causes the piezoelectric crystal to vibrate. This vibration is largest at resonance, and is then passed through the medium as a longitudinal wave. i.e., a sound wave is produced.

  3. Magnetostriction generator:   In this method, the magnetostriction method is used for the production of ultrasonic. Frequencies ranging from 8000 Hz to 20,000Hz can be produced by this method.

Ultrasonic Interferometer:

The schematic diagram of an ultrasonic interferometer is shown below.


In an ultrasonic interferometer, the ultrasonic waves are produced by piezoelectric method. In a fixed frequency variable path interferometer, the wavelength of the sound used is measured, and from this one can calculate its velocity through that medium. The apparatus consists of an ultrasonic cell, which is a double walled brass cell with chromium plated surfaces and has a capacity of 10ml. The schematic diagram of an ultrasonic interferometer is shown below. The micrometer screw has a least count of 0.001cm and pitch scale has a length of 25mm. Ultrasonic waves of known frequency are produced by a quartz crystal which is fixed at the bottom of the cell. There is a movable metallic plate parallel to the quartz plate, which reflects the waves. These waves superimpose and if the separation between the plates is exactly a whole number multiple of wavelength of sound, standing waves are produced in the liquid medium. At this point, acoustic resonance occurs and this give rise to an electrical reaction on the generator driving quartz plate. Now the anode current of the generator becomes maximum.

If we increase or decrease the distance and the variation is exactly one half of the wavelength (λ/2) or its multiple, the anode current again becomes maximum. If ‘d’is the   separation between successive adjacent maximum anode current, then,

d = λ/2.

v:unknown * { BEHAVIOR: url(#default#VML) } o:unknown * { BEHAVIOR: url(#default#VML) } w:unknown * { BEHAVIOR: url(#default#VML) } .shape { BEHAVIOR: url(#default#VML) }

We have, the velocity (v) of a wave is related to its wavelength (λ) by the relation,

                                   v=fλ, where f is the frequency of the wave.

                                   Then,   v= λf= 2df.

The velocity of ultrasound is determined principally by the compressibility of the material of the medium. For a medium with high compressibility, the velocity will be less. Adiabatic compressibility of a fluid is a measure of the relative volume change of the fluid as a response to a pressure change. Compressibility is the reciprocal of bulk modulus, and is usually denoted by the Greek word beta (β).The adiabatic compressibility of the material of the sample can be calculated using the equation,


  where ρ is the density of the material of the medium and v is the velocity of the sound wave through that medium.

3 years ago

Post Your Answer

More Questions On General Physics

Ask Experts

Have any Question? Ask Experts
Post Question
Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details
two wires x,y have the same resistivitybut the crosssection areas are in,the ratio2:3 and lengths are in the ratio 1:2 .they are first connected in series and then in parallel to a DC sourse...
Dear student, First find the ratio of the resistances of two wires using the formula for R. Find the equivalent resistance in both the combinations and find the corresponding current and...
Shobhit Varshney one month ago
Does the area of contact between the object and the ground affect the amount of force required to move the object if there is friction?Please explain .
Hi rahul No friction force does not depend upon the area of contact as long as the Normal force is constant
There is a derivation given in my book which concludes to the fact that the range is same for two angles of projection, provided they are complementary. I fail to understand this fact. For...
Range is the horizontal displacement by projectile in the time in which the body is above the horizontal level(ground).Or we can say Range = orizontal component of velocity x T..,where T is...
Shivam 3 months ago
A light ray is travelling from air to glass.The reflected and refracted rays are perpendicular to each other.If the angle of incidence in air is i.the refractive index of glass is?
According to brewsters law, when a ray of light is incident on optical medium, and undergoes simultaneous reflection and refraction such that the reflected and refracted rays are...
Karan Tewani one year ago
By snell''s law n a sin(i)=n b sin(90-i) sin(i)=n b Cos(i) (n a =1) sin(i)/Cos(i)=n b n b =Tan(i) The refractive index of glass is Tan(i)
one year ago
we can get the answer by using snells law: na*sin(i)=nb*sin(r).
G.Rajashekar one year ago
a heavy uniform straight rod is suspended from apont by two strings of the same length as the rod attached to its ends.if one string is cut prove that the initial angular acceleration of the...
Dear student, Find out the tension in the string and draw the FBD of the rod and the string just after the string is cut. Find out the unbalanced forces and find the accelerations, Good luck...
Shobhit Varshney 2 months ago
sir i tried to do it as mentioned by you before posting this question on this forum but still could not succeed by equation mg-t=ma and mgl/2=ml2/3alpha and a=l/2alpha with this t=mg/4 and...
arun gupta 2 months ago
will two magnets lose magnetism if they stick to each other for infinitely long time?
Magnetism is not due to electric charges. Practically, the magnets lose their magnetism if they stick to each other for a long time. Theoretically, considering them as perfect magnets. No,...
Sher Mohammad 6 months ago
View all Questions »