Elec Class

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Solved exercise · level 4 of 5

Height of a waterfall

Skills: Calculate

Statement

A generator delivering 20.48 kW, with an efficiency of 0.87, is driven by a turbine of efficiency 0.8 fed with 15 m³/min from a waterfall. Determine the height of the fall.

P₃ = 20.48 kW · ηg = 0.87 · ηt = 0.8 · qv = 15 m³/min

Parametric exercise: the values change with every draw; these are one example.

Guided problem in 4 steps: unknown, formula, units, data, result.

1 hint from Bastaya available in the lab
Solution

P₁ = P₃ / (ηt · ηg) = 29.43 kW; h = P₁ × 60 / (m × g) with m = 15 × 1,000 kg per minute → h = 12 m.

Course sheet of the chapter : Power, energy, efficiency

This chapter is covered by the paths: General electricity, ISL-oriented exercises

Other exercises of the chapter

Simulated time00:00:00
Q = I·t-
W = P·t-

Circuit diagram CEI 60617

How does it work?

Each big hole is a circuit node: you push one leg of a component into it. The 4 small holes around it are connected to it: chips and leads plug in there.

  1. Place a component Drag it from the palette: it snaps onto the grid. R rotates it.
  2. Bridge neighbouring holes Pick the jumper chip (or C) and drag on the board: bridged holes become a single node.
  3. Draw a lead For long links and the power supply: from one big hole to another, or to a terminal.
  4. Close the loop The circuit is solved live (Ohm, Kirchhoff) and the diagram follows.

Shortcuts

Del
delete
R
rotate
C
chip brush
Esc
cancel
wheel
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fit the board
drag background
pan

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