Question 1
Which energy source primarily relies on the conversion of sunlight into electricity using semiconductors?
A. Wind Energy
B. Geothermal Energy
C. Solar Energy
D. Tidal Energy
Question 2
What is a primary environmental concern associated with hydroelectric dams?
A. Air pollution
B. Habitat destruction
C. Nuclear waste
D. Greenhouse gas emissions
Question 3
Which energy source involves harnessing heat from the Earth's core?
A. Solar Energy
B. Biomass
C. Geothermal Energy
D. Wind Energy
Question 4
Which of the following is NOT a type of fossil fuel?
A. Coal
B. Oil
C. Uranium
D. Natural Gas
Question 5
What is the primary challenge associated with wind energy?
A. Radioactive waste
B. Intermittency
C. Greenhouse gas emissions
D. Habitat destruction
Question 6
a) A photovoltaic cell with an efficiency of 20% is exposed to sunlight with an intensity of 600 W/m^2. Calculate the power output per square metre of the cell. [2]
b) If the cell has an area of 1.5 m^2, determine the total power output of the cell. [2]
Question 7
a) A wind turbine with a blade length of 50 m rotates at 15 revolutions per minute (rpm). Calculate the linear speed of the tip of the blade. [2]
b) If the wind speed is 12 m/s, and the turbine operates at 40% efficiency, determine the power extracted from the wind by the turbine. Assume air density to be 1.225 kg/m^3. [2]
Question 8
a) A geothermal plant extracts 5000 kg of steam per hour from the Earth's core at a temperature of 400°C and uses it to heat water from a river at 20°C. Calculate the heat energy transferred from the steam if its specific heat capacity is 2.1 J/g°C. [2]
b) If the geothermal plant operates at an efficiency of 30%, determine the useful energy output from the extracted heat. [2]
Question 9
a) Explain the working principle of photovoltaic cells in converting sunlight into electricity. [3]
b) What challenges are faced in terms of energy storage for solar farms? [2]
c) Calculate the energy output of a solar farm if it has an efficiency of 20% and receives sunlight with a power of 600 W/m^2 over an area of 2000 m^2 for 5 hours. [3]
Question 10
a) Describe the environmental impact of wind farms. [3]
b) If a wind turbine has a blade length of 50m, calculate the swept area of the turbine. [2]
c) Given that the air density is 1.225 kg/m^3 and the wind speed is 10 m/s, calculate the power available in the wind that can be harnessed by the turbine. [3]