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High School/JEE/NEET/IPhO Physics | 17-19 Yrs

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  1.  
  2. The grandmaster of Physics . Thank you sir .
    4 months ago by

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  3.  
  4. why to tension the ball we will up
    2 years ago by surekha ade

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  5.  
  6. Sir, will the excess pressure not be 4T/r since its an air bubble?
    3 years ago by Anurag Mishra

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  7.  
  8. why can't the radius be different from 1mm/2 ?
    5 years ago by Arundhati Argon

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  9.  
  10. sir where is boyant force in this Q. ?
    5 years ago by Jatin Kr

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  11.  
  12. sir kya ye sara video important hai board exams ke liye
    5 years ago by Saurav Tiwari

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  13.  
  14. sir shape of meniscus is due to forces of cohesion and adhesion or due to excess pressure?
    5 years ago by rishi shrivastva

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  15.  
  16. sir, I can't understand this experiment . have this experiment any name so that I can find it YouTube . or have this experiment is in any video of youtube .if you give me this link i can directly watch this.....
    5 years ago by Ujjwal Kar

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  17.  
  18. Sir,Why you considered only the left side of the Ring ?? Why not the full Ring ??
    5 years ago by Sourav Jayson

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  19.  
  20. Sir why here Pa-Pb is 2T/R?
    5 years ago by prahas ranjan

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  21.  
  22. Sir pls reply I'm not able to understand
    5 years ago by prahas ranjan
    Ans 1 ->
    Sir pls reply .you are the only source for me for studying physics .pls sir pls??
    5 years ago by prahas ranjan

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  23.  
  24. Sir can you please explain that why you took the surface tension force in tangential direction and why you multiplied T with R2 cos phy instead of R1 cos they at 2:53 ? Sir please reply I m not able to continue with this chapter because of this doubt .pls reply
    5 years ago by prahas ranjan
    Ans 1 ->
    Sir why did you multiply T with r2 cos phy
    5 years ago by ANUJ gupta

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  25.  
  26. sir in this Q how you get to know whether the bubble is single layer or double layer so that you have applied formula 4T/R in the Q
    6 years ago by Teena ashiya
    Ans 1 ->
    for a bubble we always take 4T/R, cuz it has two free surfaces
    5 years ago by Lalith

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  27.  
  28. Sir here Press at b is 2T/r2. Is the expression for difference in pressure just the reverse
    6 years ago by Sankalpa Bhattacharya

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  29.  
  30. I can't understand why we consider only two T's acting in downward direction, why can't more?
    6 years ago by HARSHA DARBHASAYANAM

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  31.  
  32. Why we have taken force on curvature as tension into length of other curvature
    6 years ago by

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  33.  
  34. Sir while finding the radius of the liquid drop why are we not considering twice the surface area of bubble as we have considered in other cases
    7 years ago by Raghav G

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  35.  
  36. sir in the case of water glass pair when a drop of water fall on the surface there exist 3 forces one is due to adhesive force of air and liquid 2nd is due to adhesive force of liquid and solid and 3rd is due to adhesive force between solid and air .This is solid and air adhesive force How can it act on the drop of water ?? and why we consider that force??
    7 years ago by Advait Kulkarni

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  37.  
  38. sir why there will be only two surfaces ?
    7 years ago by Advait Kulkarni
    Ans 1 ->
    There are infinite layers in soap film but only two free surface where surface tension acts.
    6 years ago by Rupesh Koirala

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  39.  
  40. sir why didn't we take the force acting on the ring from the other side ??
    7 years ago by Advait Kulkarni

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  41.  
  42. I have a doubt in the question from HCV chapter 14 question 29:can anyone explain the question to me?
    7 years ago by Nikunj Bagri

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  43.  
  44. How can we say that Pressure at A is greater than Pressure at B?
    7 years ago by Ardhendu Shekhar
    Ans 1 ->
    In concave(concavity) side the pressure is high. How? Consider a straight log of wood. Try to bend it into a bow(Dhanus). If you do it, a concave log of wood is formed. What must you do to make such bow? You must apply force towards the centre from two ends of the log of wood. In this similar analogy, this force tries to squeeze the film and pressure inside increases. So pressure is greater on concave side. Brush your knowledge, In star nuclear fusion occours when gravity tries to squeeze it's core and pressure is increased which maintains hydrostatic equilibrium increasing temperature of star resulting into fusion. So stars are circle ie. they have more pressure in concave side when T.S. is cut of part of it. Sun is also a star.
    6 years ago by Rupesh Koirala

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  45.  
  46. Why the force needed to separate the two plates is (Patm-PB)A and not (Patm+PB)A?
    7 years ago by Mayank Agrawal
    Ans 1 ->
    as Patm and Pb are opposite in direction and so net pressure is inside which is (Patm-Pb)A
    7 years ago by pawn kumar

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  47.  
  48. Sir is it true that if I place a thread in a circular shape initially only on a soap film,and prick it,then it willn't expand?
    7 years ago by Harshit Rawat

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  49.  
  50. Respected sir, i have a doubt here.if we consider a particle deep inside the container then it will experience a force in all directions due to sphere of influence so it will have net force zero and will feel a pressure so every particle will be stretched due to this pressure and hence there should be tension at any surface below the free surface.am i right in this sense.please explain?
    7 years ago by jeevan99

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  51.  
  52. Sir please explain how does surface tension tends to minimize the surface area of a free liquid surface
    8 years ago by Harshit Rawat
    Ans 1 ->
    Due to surface tension the liquid surface tend to behave like a stretched rubber membrane in which all molecules attract each other and the surface tend to contract...
    8 years ago by Physics Galaxy

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  53.  
  54. In a liquid enclosed in a vessel, the particle at the edges experience an unbalanced force then why does the surface remains stationary?
    8 years ago by Harshit Rawat
    Ans 1 ->
    It is not unbalanced... its balanced by the net contact force on each molecule due to other neighbouring molecules...
    8 years ago by Physics Galaxy

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  55.  
  56. sir would the answer had been same if it were a disk???
    8 years ago by Arunava Benz

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  57.  
  58. Sir I have a doubt in a similar question that was asked in jee main. In that question if i just conserve initial and final energy i dont get the right ans.But if i do it with integration i get it right.The ques is.............Assume that a drop of liqd evaporates by decrease in its surf energy so that its temp remains const.what shud be the min radius of drop for this to be possible. (T--surf tension;rho- density of liqd;L---latent heat of vap)....ans...2T/rho*L.... (PLEASE TELL ME WHY THE ABOVE SOLVED PROB WAS NOT DONE BY INTEGRATION).....Thnxs and sorry for the long ques.
    8 years ago by Mohak Sharma
    Ans 1 ->
    Mohak sharma you can also use online forums like physicsforum physics stack exchange for clearing doubts
    8 years ago by Ajay Sabarish

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  59.  
  60. but sir if we think practically then whatever the water we pour in the cylinder all of that will be leaked out.
    8 years ago by sagar choudhury

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  61.  
  62. In deriving excess pressure inside we should consider external atmospheric pressure also?
    8 years ago by Sai Shravanth Reddy

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  63.  
  64. sir why are we taking twice of the surface area in each of the question..?? plz explain...
    8 years ago by Khushboo Jain
    Ans 1 ->
    Theformula(F=TL) givesforcebeingappliedfromoneside inquestions whereforce canbeappliedfrommorethanonesidethenindividualforcesshould beconsidered
    7 years ago by Anshul garg

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  65.  
  66. why the water level is more in narrow bore ?
    8 years ago by kartik chandna

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  67.  
  68. considered the two edges but what about the portion between the edges liquid will stick to that also .. ??
    8 years ago by ABHISHEK MALAKAR

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  69.  
  70. when the pressure in both sides will be equal no further flow of air takes place in that case if we equate P1=P2 then we get R1=R2 .. what is that then ???
    8 years ago by ABHISHEK MALAKAR
    Ans 1 ->
    Nope. The case is dP= T(1/r 1/R) . In that case R will be - in smaller balloon. and R can't be equated.
    6 years ago by Rupesh Koirala
    Ans 2 ->
    in between
    6 years ago by Rupesh Koirala
    Ans 3 ->
    Plus sign is in between of 1/r 1/R
    6 years ago by Rupesh Koirala

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  71.  
  72. not understood at all :(
    8 years ago by ABHISHEK MALAKAR

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  73.  
  74. Sir how to find force if a sphere or a cube of mass m are given. In that case for writing expression for suface tens as T=F/L what L has to be taken for sphere and cube?
    8 years ago by Mohak Sharma

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  75.  
  76. sir, not able to understand why the force is acting downwards
    9 years ago by adharsh p
    Ans 1 ->
    Force due to surface tension always act along the surface of liquid. Here when the rod is lifted up, surface of liquid in contact with the rod will become vertical so it will be acting in downward direction...
    9 years ago by Physics Galaxy

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  77.  
  78. an open rectangular tank with base area 5 m *4 m and height 3 m containing water upto a height of 2 m is accelelarated horizontally along right side. 1)determine the maximum acceleration that can be given without spilling the water. 2)calculate the percentage of water split over ,if this acceleration is increased by 20%. 3) if initially the tank is closed at the top and is accerated horizonltally by 9 m/s2, what is the gauge pressure at the bottem of the front and rear walls of the tank.
    9 years ago by laxman bodala

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  79.  
  80. what is the difference between a hemispherical and a sub-hemispherical soap bubble, which one will have a greater radius and why? something relating to it was asked in iit jee 2008 3M ...pls help
    9 years ago by jodupynadath

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  81.  
  82. what is the difference between angle of contact 0, 90 and 180 degrees, and how does each one look like? i am confused pls help
    9 years ago by jodupynadath

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  83.  
  84. solved example surface tension (ST8X5) WHAT IS THE ANGLE AT THE POINT OF CONTACT OF THESE THREE SURFACES?
    9 years ago by ramesh nagda

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  85.  
  86. what is the surface tension acting on the sphere placed on liquid surface?
    9 years ago by Aditya Pandey
    Ans 1 ->
    Surface tension = (mg)/2L I'm taking force of surface tension to act downwards...:)
    7 years ago by Anshul garg

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  87.  
  88. what is the value of surface tension at the uppermost layer of atmosphere
    10 years ago by deepansh

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  89.  
  90. Why will surface tension not act on complete hemisphere? Why will it only act on the outermost circumference?
    10 years ago by manish reddy yedulla
    Ans 1 ->
    Surface tension shall act between any 2 molecules inside the sphere but it is only an internal force hence it will cancel out.Imagine you draw a line in the inner part of the sphere it will be acted upon by forces on its both sides,but on the circumference there is only one side(which is under consideration )hence the forces will not cancel out.
    9 years ago by Sanjay

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  91.  
  92. Why will surface tension not act on complete hemisphere? Why will it only act on the outermost circumference?
    10 years ago by manish reddy yedulla

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  93.  
  94. Respected sir, i have a doubt here.if we consider a particle deep inside the container then it will experience a force in all directions due to sphere of influence so it will have net force zero and will feel a pressure so every particle will be stretched due to this pressure and hence there should be tension at any surface below the free surface.am i right in this sense.please explain?
    10 years ago by ARVIND SHARMA

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