Surveying Multiple Choice Questions on “Hydrographic Survey – Rain Gauging”.
1. Rain gauge is used for ________
a) Hydrological survey
b) Measuring precipitation
c) Marine survey
d) River survey
Answer: b
Clarification: Rain gauge is used by the meteorologists for measuring the amount of precipitation over the time period considered. The instrument gives the best result when it is placed in an open area.
2. Rain gauge is expressed in terms of _________
a) Decimeters
b) Meters
c) Centimeters
d) Millimeters
Answer: d
Clarification: The amount of precipitation measured in terms of the height of the precipitated water accumulated in the container per given time and is expressed in terms of millimeters.
3. Calculate the total rainfall in an interval, where volume of the bucket is taken as 24cu. m and time interval N = 3.
a) 72cu. m
b) 2cu. m
c) 27cu. m
d) 72sq. m
Answer: a
Clarification: The total rainfall in the given interval is determined by using the formula,
Rainfall = N*v. on substitution, we get
Rainfall = 3*24 = 72cu. m.
4. Find the least count of the instrument used in case of rainfall determination, if the volume of the bucket is 50cu. m and the area of the funnel is about 21 sq. m.
a) 3.38 m
b) 2.83 m
c) 2.38 m
d) 4.38 m
Answer: c
Clarification: The least count of the instrument can be given as
K = v / A. on substitution, we get
K = 50 / 21 = 2.38 m.
5. What would be the rate of rainfall if the value of N can be given as 2 and the difference in time can be given as 24 sec with the L.C of the instrument as 1m?
a) 50m-sec
b) 48m-sec
c) 42m-sec
d) 49m-sec
Answer: b
Clarification: The rate of rainfall can be determined by using the formula,
R = N*k*δt. On substitution, we get
R = 2*1*24
R = 48m-sec.
6. Tipping bucket used in the rain gauge will turn under the action of ___________
a) Battery
b) Hand movement
c) Gravity
d) Motor
Answer: c
Clarification: Tipping bucket is provided in the rain gauge for collecting the required amount of rainfall needed for measurement of the precipitation in the atmosphere. After being filled to the maximum level, the tipping bucket will turn under the action of gravity.
7. Which of the following rain gauge equipment is used in case of remote areas?
a) Reflective rain gauge
b) Acoustic rain gauge
c) Optical rain gauge
d) Tipping bucket
Answer: d
Clarification: Due to the unavailability of the machinery and all other equipments in the remote areas, tipping bucket method can find its advantage. It requires no machine interpretation and is able to deliver accurate value for measuring precipitation.
8. Rain gauge is also known as __________
a) Udometer
b) Opto meter
c) Luda meter
d) Rio meter
Answer: a
Clarification: The equipment which involves in the determination of the precipitation levels in the atmosphere is termed as a rain gauge. It is also known as ombro meter or the udometer based on the area it is in use.
9. Which of the following will not come under the classification of rain gauge?
a) Tipping bucket gauge.
b) Reflective rain gauge
c) Optical rain gauge
d) Acoustic rain gauge
Answer: b
Clarification: Rain gauge has been classified based on the type of work being conducted to adapt the situations. Those include optical rain gauge, acoustic rain gauge and tipping bucket gauge.
10. Acoustic rain gauge can also be known as__________
a) Hydro gauge
b) Hydro remote
c) Hydrophone
d) Hydro cable
Answer: c
Clarification: Acoustic rain gauge is also referred as a hydrophone, is able to sense the sound signature from each drip of rainfall that strikes the surface. It is possible to invert the underground sound field to estimate the drop size distribution.