# Fluid Mechanics Questions and Answers – Most Economic Circular Section – 2

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Most Economic Circular Section – 2”.

1. Estimate the hydraulic depth for a most economical circular channel section in case of maximum velocity.
a) 0.2D
b) 0.3D
c) 0.4D
d) 0.5D

2. What is the value of θ in a most economical circular section in case of maximum discharge?
a) 150°
b) 152°
c) 154°
d) 156°

Explanation: The equation in case for maximum discharge is,
4Ɵ – 6θ cos⁡ 2θ + sin ⁡2θ = 0 where θ = 154°.

3. Calculate the depth in a most economical circular section in case of maximum discharge.
a) 0.65D
b) 0.75D
c) 0.85D
d) 0.95D

4. Calculate the hydraulic radius of a circular channel in case of maximum discharge if the radius of the channel is 4m.
a) 1.7m
b) 2.0m
c) 2.3m
d) 2.6m

5. Calculate the wetted area of a circular channel section in case of maximum velocity.
a) 5.47m2
b) 6.47m2
c) 7.47m2
d) 8.47m2

6. Calculate the wetted perimeter of the most economical circular section having radius 3m in case of maximum discharge.
a) 15.12m
b) 16.12m
c) 17.12m
d) 18.12m

Explanation: P = 2Rθ = 2(3)(2.6864) = 16.12m.

7. What is the value of wetted perimeter of a circular section having radius 6m in case of maximum velocity?
a) 12.47m
b) 13.47m
c) 14.47m
d) 15.47m

Explanation: P = 2Rθ = 2(6)(2.2460) = 13.47m.

8. Estimate the value of wetted area of a circular section in case of maximum discharge if the radius of the channel is 7m.
a) 134m2
b) 144m2
c) 154m2
d) 164m2

9. Calculate the hydraulic radius in case of maximum velocity if the radius of the section is 8m.
a) 7.87m
b) 6.87m
c) 5.87m
d) 4.87m

10. Calculate the discharge through a most economical circular section in case of maximum velocity if the radius of the channel is 0.5m, bed slope of 1 in 500 and the value of n = 0.016.
a) 0.43 m3/s
b) 0.53 m3/s
c) 0.63 m3/s
d) 0.73 m3/s

Sanfoundry Global Education & Learning Series – Fluid Mechanics.

To practice all areas of Fluid Mechanics, here is complete set of 1000+ Multiple Choice Questions and Answers. 