Question

A dam is situated at a height of 550 metre above sea level and supplies water to a power house which is at a height of 50 metre above sea level. 2000 kg of water passes through the turbines per second. The maximum electrical power output of the power house if the whole system were 80% efficient is

• A. 8 MW
• B. 10 MW
• C. 12.5 MW
• D. 16 M

Answer 1

Answer: (A)

8 MW

Answer 2

$\text{Power} = \frac{\text{work done}}{\text{time}} = \frac{mg\Delta h}{t} = \frac{2000 \times 10 \times (550 - 50)}{1} = 10MW$But the system is 80% efficient

∴ Power output = 10 × 80% = 8 MW.