Engineering Questions with Answers - Multiple Choice Questions

# MCQs on Discharge Over different type of weirs

1 - Question

In discharge of water over narrow crested weir, head of water is directly proportional to Discharge Coefficient.
a) True
b) False

b
Explanation: In discharge of water over narrow crested weir, head of water is inversely proportional to Discharge Coefficient.

2 - Question

In discharge of water over narrow crested weir, discharge is directly proportional to the cube root of acceleration due to gravity.
a) True
b) False

b
Explanation: In discharge of water over narrow crested weir, discharge is directly proportional to the square root of acceleration due to gravity.

3 - Question

In discharge of water over ogee weir, discharge is directly proportional to the second power of length.
a) True
b) False

b
Explanation: In discharge of water over ogee weir, discharge is directly proportional to the first power of length.

4 - Question

For discharge over ogee weir discharge is directly proportional to length but for discharge over narrow crested weir it is inversely proportional to length.
a) True
b) False

b
Explanation: For both weirs it’s same.

5 - Question

An Ogee weir 5 m long had a head of 40 cm of water. If CD = 0.61, find the discharge over the weir.
a) 2.9 m3/s
b) 2.3 m3/s
c) 3.1 m3/s
d) 3.3 m3/s

a
Explanation: Q = 0.67 * Cd * L * √2g * H1.5
Q = 2.3 m3/s.

6 - Question

The height of water on upstream and downstream side of a submerged weir of 4 m length are 24 cm and 13 cm. If Cd for free and drowned portions are .62 and .78 respectively, find the discharge over the weir.
a) .85 m3/s
b) 1.35 m3/s
c) 3.2 m3/s
d) .55 m3/s

a
Explanation: Q = 0.67 * Cd1 * L * √2g * H1.5 +. Cd2 * L * h * √2g(H – h)
= .67 * .6 * 3 * √2g * (.24 – .13)1.5 + .8 * 3 * .13 √2g(.24 – .13)
= .85 m3/s.

7 - Question

An Ogee weir 3.4 m long had a head of 40 cm of water. If CD = 0.63 find the discharge over the weir.
a) 1.61 m3/s
b) 2.5 m3/s
c) 3.1 m3/s
d) 3.3 m3/s

a
Explanation: Q = 0.67 * Cd * L * √2g * H1.5
Q = 1.61 m3/s.

8 - Question

The height of water on upstream and downstream side of a submerged weir of 4 m length are 23.5 cm and 14 cm. If Cd for free and drowned portions are .61 and .75 respectively, find the discharge over the weir.
a) m3/s
b) 1.35 m3/s
c) 3.2 m3/s
d) .55 m3/s

a
Explanation: Q = 0.67 * Cd1 * L * √2g * H1.5 +. Cd2 * L * h * √2g(H – h)
= .67 * .6 * 3 * √2g * (.24 – .13)1.5 + .8 * 3 * .13 √2g(.24 – .13)
= .85 m3/s.

9 - Question

In discharge of water over narrow crested weir, discharge is directly proportional to the second power of height.
a) True
b) False

b
Examples: In discharge of water over narrow crested weir, discharge is directly proportional to the one and half power of height.

10 - Question

In discharge of water over Ogee weir, discharge is directly proportional to the first power of length.
a) True
b) False