Irrigation Engineering Multiple Choice Questions on “Regulation Modules – Outlet Types”.
1. What is the main purpose of the canal outlet?
a) To Connect Head with a Minor Channel
b) To Avoid Leakage
c) To Avoid Exit Gradient
d) For Proper Discharge
Answer: b
Clarification: The canal outlet is a small structure that is built at the head of the watercourse so as to connect it with a distributary channel or a minor channel.
2. How many types of outlets are present?
a) 2
b) 3
c) 4
d) 5
Answer: b
Clarification: The available types of outlets are classified into three classes. These classes are non-modular outlets, semi-modules, and rigid modules.
3. Which structure in the entire network of canals is a link between the government and the cultivators?
a) Weirs
b) Falls
c) Modules
d) Canal Escapes
Answer: c
Clarification: In the entire network of the canals, up to the modules the control and maintenance falls under the jurisdiction of state government, and beyond the modules the entire working of water courses is takencare by the cultivators. Hence the modules are the structures which provide the link between government and the cultivators.
4. The outlet should be cheap and with no moving parts.
a) True
b) False
Answer: a
Clarification: Since these outlets are required in large numbers, they should be cheaply available. And moreover the outlets should be sufficiently strong enough with no moving parts, to avoid periodic maintenance.
5. The outlet should be simple and free from interference by the cultivators.
a) True
b) False
Answer: a
Clarification: The outlet or module should be simple because it can easily be constructed or fabricated by the masons or technicians. Interference with the cultivators should also be avoided to prevent undue tapping of water by the cultivators.
6. Open sluice and drowned pipe outlet come under which class of modules?
a) Modular Outlets
b) Semi Modules
c) Rigid Modules
d) Non-modular Outlets
Answer: d
Clarification: In open sluice or drowned pipe outlet the discharge depends upon the difference between the head in a distributary and the water courses. The discharge in these two also vary widely either with a change in the water level of the distributary or that of a water course. Hence, the open sluice and drowned pipe outlet come under non-modular outlets class.
7. What is the common example of rigid modules?
a) Pipe Outlet
b) Open Sluice
c) Gibb’s Module
d) Venturi Flume
Answer: c
Clarification: In Gibb’s module the discharge is constant within the fixed limits, irrespective of variation of water levels of either the distributary or of a water course or both. Thus Gibb’s module is a common example of a rigid module.
8. In which class of outlets the discharge is independent of water level of the water course?
a) Non-modular Outlets
b) Semi Modules
c) Rigid Modules
d) Modular Outlets
Answer: b
Clarification: The outlets in the class of semi-modules are those in which the discharge is independent of the water level of the water course but depends only on the water level of the distributary as long as a minimum working head is available. Therefore, the discharge is directly proportional to the water surface level in the distributary.
9. When the flexibility of an outlet equals unity, then the outlet is said to be in?
a) Sub-proportional
b) Setting
c) Sensitivity
d) Proportionality
Answer: d
Clarification: An outlet is said to be proportional when the rate of change of outlet discharge equals the rate of change of channel discharge or in other words, we can say when flexibility equals unity then the outlet is proportional or in proportionality. Hence, F = (m/n) x (y/H) = 1.
10. For which type of class of outlets the sensitivity is zero?
a) Rigid Modules
b) Semi Modules
c) Non-modular Outlets
d) Flexible Modules
Answer: a
Clarification: The ratio of rate of change of discharge through the outlet to the rate of change of water level of distributary, to the normal depth of the channel is known as sensitivity. Since the discharge is fixed for rigid modules the sensitivity is zero.
11. What is the minimum difference between the upstream and downstream water levels to allow designed discharge through the module?
a) Minimum Modular Depth
b) Efficiency of an Outlet
c) Drowning ratio
d) Proportionality
Answer: a
Clarification: A minimum difference between the water levels of both upstream and downstream is to be maintained so as to enable the module to pass the designed discharge is known as minimum modular head.
12. What is the ratio of the depth of water levels over the crest is called?
a) Efficiency of an Outlet
b) Drowning Ratio
c) Minimum Modular Head
d) Modular Limit
Answer: b
Clarification: The ratio of the depth of water level over the crest on the downstream side to the depth of water level over the crest on the upstream side is called a drowning ratio.
13. What is the ratio of head output to the head input called?
a) Modular Limit
b) Minimum Modular Head
c) Efficiency of an Outlet
d) Drowning Ratio
Answer: c
Clarification: The ratio of head recovered (output) to the head put in (input) is known as efficiency of an outlet. If the head required for the operation that is head put in, is less more will be the efficiency. This efficiency is also a measure of conservation of head by the outlet.