Question

Coefficient of viscosity (η) is represented by rate of flow of liquid in narrow tube according to following relation:

η = \(\frac{\pi Pr^4}{8Vl}\)

where all quantities are in their usual meaning. 

Values of P, r, V and l are 76 cm of Hg, 0.28 cm, 1.2 cm³ s^-1 and 18.2 cm. If accurate measurement of these quantities is 0.1 cm of Hg, 0.01 cm cm³ s^-1 and 0.1 cm. Determine the percentage error in the value of q.

Answer 1

P = 76.0 cm ⇒ ∆P = 0.1 cm

r = 0.28 cm ⇒ ∆r = 0.01 cm

V = 1.2 cm³ s^-1 ⇒ ∆V = 0.1 cm³ s^-1

l = 18.2 cm ⇒ ∆l = 0.1 cm