Question

Write dimensional formula of coefficient of viscosity

(a) M¹L²T^-1

(b) M^-1L¹T¹

(c) M¹L^-1T^-1

(d) M¹L¹T^-1

Answer 1

Correct option (c) M¹L^-1T^-1

Explanation:

coefficient of viscosity = [(stress) / (velocity gradient)]

= [{(Force) / (Area)} / {(Δ Velocity) / (distance)}]

 = [(F/A) / (ΔV/S)]

Force = mass × acceleration = ma;

change in velocity = [(change in distance) / (time)]

∴ coefficient of viscosity = [(F/A) / (ΔV/S)] = [(ma ∙ s) / (A ∙ ΔV)]

 = {([M¹L¹T^–2][L]) / ([L²][L¹T^–1])}

 = [M¹L^–1T^–1]