Answer
386.4k+ views
Hint:Consider the small arc of the thread in the circular loop. Determine the expression for the surface tension of the soap solution on this thread arc and the tension experienced by the thread in the opposite direction to that of the tension due to the soap solution. Thus, derive an expression for the tension in the thread.
Formula used:
The arc \[s\] of cone is given by
\[s = R\theta \] …… (1)
Here, \[R\] is the radius of the cone and \[\theta \] is the angle subtended by the cone.
Complete step by step answer:
We have given that the thread placed on the horizontal film of soap solution forms a loop. But when the film is punctured inside the loop, the thread forms a circular loop of radius \[R\]. The surface tension of the soap solution is \[T\]. Let us consider a small arc of the circular loop formed by the thread when the film is punctured.
In the above figure, \[\theta \] is the angle subtended by the small cone, \[T\] is the surface tension in the soap solution and \[T'\] is the tension experienced by the thread. The components of the tension experienced by the thread are shown in the above diagram.The total tension exerted by the soap solution film on the small length \[\Delta l\] of the thread is \[2T\Delta l\].
This tension exerted by the soap solution is balanced by the vertical component of the surface tension experienced by the thread.
\[2T\Delta l = 2F\sin \dfrac{\theta }{2}\]
\[ \Rightarrow T\Delta l = F\sin \dfrac{\theta }{2}\]
The angle in the above equation is very small. Hence, the above equation becomes.
\[ \Rightarrow T\Delta l = F\dfrac{\theta }{2}\]
According to equation (1), substitute \[R\theta \] for \[\Delta l\] in the above equation.
\[ \Rightarrow TR\theta = F\dfrac{\theta }{2}\]
\[ \therefore F = 2RT\]
Therefore, the tension in the thread will be \[2RT\].
Hence, the correct option is D.
Note:One can also show that the tension due to the soap solution is balanced by the vertical component of the tension experienced by the thread by using Newton’s second law of motion as the thread is in a steady state when it forms a circular loop. One should always remember that the angle subtended by the arc of the thread is very small, so sine of angle is equal to angle.
Formula used:
The arc \[s\] of cone is given by
\[s = R\theta \] …… (1)
Here, \[R\] is the radius of the cone and \[\theta \] is the angle subtended by the cone.
Complete step by step answer:
We have given that the thread placed on the horizontal film of soap solution forms a loop. But when the film is punctured inside the loop, the thread forms a circular loop of radius \[R\]. The surface tension of the soap solution is \[T\]. Let us consider a small arc of the circular loop formed by the thread when the film is punctured.
![seo images](https://www.vedantu.com/question-sets/d12057e2-5c61-492c-a4ab-c09ea36daa346556438534981378395.png)
In the above figure, \[\theta \] is the angle subtended by the small cone, \[T\] is the surface tension in the soap solution and \[T'\] is the tension experienced by the thread. The components of the tension experienced by the thread are shown in the above diagram.The total tension exerted by the soap solution film on the small length \[\Delta l\] of the thread is \[2T\Delta l\].
This tension exerted by the soap solution is balanced by the vertical component of the surface tension experienced by the thread.
\[2T\Delta l = 2F\sin \dfrac{\theta }{2}\]
\[ \Rightarrow T\Delta l = F\sin \dfrac{\theta }{2}\]
The angle in the above equation is very small. Hence, the above equation becomes.
\[ \Rightarrow T\Delta l = F\dfrac{\theta }{2}\]
According to equation (1), substitute \[R\theta \] for \[\Delta l\] in the above equation.
\[ \Rightarrow TR\theta = F\dfrac{\theta }{2}\]
\[ \therefore F = 2RT\]
Therefore, the tension in the thread will be \[2RT\].
Hence, the correct option is D.
Note:One can also show that the tension due to the soap solution is balanced by the vertical component of the tension experienced by the thread by using Newton’s second law of motion as the thread is in a steady state when it forms a circular loop. One should always remember that the angle subtended by the arc of the thread is very small, so sine of angle is equal to angle.
Recently Updated Pages
Draw a labelled diagram of DC motor class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
A rod flies with constant velocity past a mark which class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Why are spaceships provided with heat shields class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
What is reflection Write the laws of reflection class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
What is the magnetic energy density in terms of standard class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write any two differences between a binocular and a class 10 physics CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Name 10 Living and Non living things class 9 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write a letter to the principal requesting him to grant class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill the blanks with proper collective nouns 1 A of class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write the 6 fundamental rights of India and explain in detail
![arrow-right](/cdn/images/seo-templates/arrow-right.png)