# Reynolds Number, Darcey - Weisbach Formula - MCQs and Answers

## Reynolds Number, Darcey - Weisbach Formula – MCQs and Answers

1. In Reynolds number (ρvd) / μ, the letter μ denotes

a. kinematic viscosity
b. absolute viscosity
c. coefficient of friction
d. none of the above

2. The ratio of inertia force to viscosity is known as

a. Biot number
b. Reynold number
c. Cauchy number
d. Euler number

3. The Reynolds number for laminar flow is

a. more than 2800
b. more than 2000
c. less than 2000
d. between 2000 and 2800.

4. A pipe has a diameter of 0.2 m in which a fluid flows with a velocity of 0.3 m3/s. Determine whether the flow is laminar or turbulent calculating the Reynolds number. Assume kinematic viscosity = 0.5 × 10-4 m2 /s.

a. the flow is laminar having Reynolds number 1200
b. the flow is turbulent having Reynolds number 2100
c. the flow is laminar having Reynolds number 2200
d. the flow is neither laminar nor turbulent

ANSWER: a. the flow is laminar having Reynolds number 1200

5. Head loss hf due to friction is given by

a. 4 ƒ l v2 / g d
b. 4 f2 l ν / 2 g d
c. 2 ƒ l v 2 / 2 g d
d. 4 ƒ l v2 / 2 g d

ANSWER: d. 4 ƒ l v2 / 2 g d

6. Head loss due to friction (hf) is a function of

3. length to diameter ratio
4. diameter to length ratio
5. friction factor

a. 1, 2 and 3
b. 1, 4 and 5
c. 1, 3 and 5
d. all the above