If an experiment to measure coefficient of viscosity radius of tube measured `r = (0.100 +- 0.001)` cm and length `1 = (50.0 +- 0.1)` cm and volume of fluid coming out of capillary in unit time is `V = (0.25 +-0.01) cm//^(2)`. If pressure difference between end of tube is `p = 10^(6)` dyne/ `cm^(2)`, then by using Poeisullie's law `V=(pi pr^(4))/(8 eta l)` Find coefficient of viscosity.

Explanation

By using Poesullie.s law.
`V=(pi p r^(4))/(8 etal)`
`:. eta=(pi p r^(2))/(8 Vl) " "...(1)`
`=(3.14xx10^(6)xx(0.1)^(4))/(8xx50xx0.25)`
`=3.14` Poise
Relative error in `eta`
`(Delta eta)/(eta)=((Deltar)/(r))+((DeltaV)/(V))+((Deltal)/(l)) " " [ :. (pi)/(8)` constant ]
`=4xx(0.001)/(0.1)+(0.01)/(0.25)+(0.1)/(50)`
`=0.04+0.04+0.002`
`=0.082`
`:.(Delta eta)/(3.14)=0.082`
`:.Delta eta=0.0082xx3.14`
`=0.25748~~0.257`
`:. eta+Deltan=(3.14+-0.257)` Poise
OR
Second method :
`(Delta eta)/(eta)xx100%=0.082xx100%`
`=8.2`
`:. eta=3.14+-8.2%` Poise