35 Replies
@Gyro Gearloose
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.anyone ...?
Is the answer to (i) P_0?
nah
yooo....?
i did not study fluid dynamics our teacher was horrible ill be covering it soon enough
but this looks cool i must say
i'm not sure about i)
ii) seems like direct formula
h for capillary rise = 2Tcos(theta) / rho*g*r
i think we assume theta (angle of contact) by default as 0 degrees so cos(theta) = 1
but
r (radius of curvature) should be given, no?I think r is supposed to ve taken as h. (Assuming theta=0)
Also assuming meniscus is spherical for some reason?
yeah fair
dodgy question
doesnt explain the underroot
in the ans
okay then,
r = h
that gives h = sqrt(2T/rho*g)sqrt nahi hota usmein
?
im substituting r = h in the capillary rise formula
as evident by this picture, i guess
if we consider the meniscus to be spherical
capillary rise = 2Tcostheta/rho g r
all the options have a sqrt too
The pressure deficit at A=$\frac{2T}{h}$ which is equal to $\rho gh$ So, $h^{2}=\frac{2T}{\rho g}$
Plug in theta=0
as for the actual ques am not sure what the ans is yet
i did find a similar one tho
Physics with Akash Goyal (PWAG)
YouTube
Surface Tension | Pathfinder Solutions | Height of Water Along a Gl...
#pathfinderphysics #jeeadvanced #propertiesofmatter
Check your understanding Q 4
when a glass plate is inserted vertically in water, water rises along plate making its surface close to the plate curved. find height to which water rises along the plate.
Yep this is it.
Ah this was a nice question. May I ask the source if you don't mind?
came in my weekly test
i have seen really good conceptual questions from this particular section of fluids
any tips for doing them
i have done surface tension and stuff only upto mains level
so basically ik formulas only
What is the ans/ options?
this was the actual ques
I'm basically recapping what was said in the video but I think the answer would be (b).
Wasn't there that relation between meniscus radius and tube radius ? r = Rcosθ iirc
Wasn't it meniscus radius=(tube radius)/cos(theta)?
Yeah.
Oh, I didn't specify
R is meniscus radius
Ah I see, Sorry.
r for tube
ig i should watch full length lecs on viscosity and not rely on formulas anymore lol
oh? i didn't know that
ill look up a proof
actually wait proof not needed
that seems intuitive
here r would be = R since contact angle theta = 0 (common default assumption)
That solution is sorta flawed I think (for this question).
Because then we are basically assuming that the meniscus is a sphere and contact angle is zero or we are assuming equivalent tube radius=h which would be wrong and give option (c).
can u share a proper soln then
This ☝️
^
will close this in a few