Question

A glass capillary tube of inner diameter 0.28 mm is lowered verically into water in a vessel. The pressure to be applied on the water in the capillary tube so that water level in the tube is same as that in the vessel is lambda xx 10^(5) N//m^(2). Then find lambda in nearest integer (surface tension of water = 0.07 N//m and atmospheric pressure = 10^(5)N//m^(2)) :

Answer 1

Answer:

Pressure due to h height column of water in tube ρgh

and By formula of rise in capillary tube of h=ρgr2Tcosθ

Taking cosθ = 1

we get Pressure = ρgh=r2T

=20.28×10−32(0.07)

= 1×103N/m2

so, pressure due to h height is 1×103N/m2 and

so, to maintain the same level in a vessel as well as in capillary tube applied pressure should be 103N/m2