21. Low discharges are effectively measured by

- Rectangular notch
- Stepped notch
- Trapezoidal notch
- Triangular notch

22. The ratio of the percentage error in the discharge and percentage error in the measurement of head over a triangular notch is

- 2/3
- 2/5
- 5/2
- 3/2

23. A triangular notch is preferred to a rectangular notch because

- only one reading is required
- its formula is simple to remember
- it gives more accurate results for low discharge
- it measures a wide range of flows accurately
- all of the above options

24. If the coefficient of discharge is 0.6, then the discharge over a right angled notch is

- 1.417 H
^{5/2} - 0.417 H
^{5/2} - 7.141 H
^{5/2} - 4.171 H
^{5/2}

25. The discharged over a triangular notch depends on the central angle of the notch, head over the notch, acceleration due to gravity and kinematics viscosity of the fluid. The number of non-dimensional terms formed for the phenomenon is

- 4
- 3
- 2
- 1