Question

1. [1pt] Decide whether each of the following statements are T-True, or F-False. (If the first is T and the rest are F, enter TFFFF)

A) About 10-15 percent of the power in the solar spectrum is in a wavelength region to which silicon photovoltaic cells are sensitive

B) If the windspeed doubles, an ideal windmill will produce double the power

C) The city of Boulder produces at most a few hundred kilowatts of electrical power from hydroelectric plants using watershed water

D) A realistic turbine in a modern windmill can convert kinetic energy of the air into electric energy at an efficiency well above 60 percent

E) A realistic turbine in a modern hydroelectric plant can convert gravitational potential energy of water into electric energy at an efficiency above 80 percent Be careful to input your answer as a string of "T's and F's", in order.

Answer 1

A) True

Current efficiency of solar cell is around 20-30%.

B) False

Power generated is proportional to . So with double of wind speed power increases to 8 times.

C) True

Power generated is of the order of 1 lakhs watt.

D) False

According to Betz's law. Theoretical power generated by windmill cannot be more than 59.3%

E) True

There is no restriction to maximum power output like wind turbines but the maximum power cannot be 100% because the water does not stop after hitting the blades of water turbines. So it is always less than 100%.