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A model of a hydraulic turbine is tested at a head of 1/4th of that under which the full scale turbine works. The diameter of the model is half of that of the full scale turbine. If N is the RPM of the full scale turbine, then the RPM of the model will be
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- N/4
- N/2
- N
- 2N
Correct Option: C
Given data:
| Model: Hm = | ;Dm = | ||
| 4 | 9 |
Nm = ?
Prototype (Full scale turbine)
Np = N
| CH = | |
| (ND)2 |
(CH)model = (CH)prototype
| = | ||
| Nm²Dm² | Np²Dp² |
| = | ||
| Nm² ×(Dp²/4) | Np²Dp² |
Nm = N
