Rsidential Solar Solution:a. A type of photovoltaic solar panel manufactured in China receives a rating of 250W. The rating process utilizes a uniform solar irradiance of 1 kW/m^2. If the solar panel has an area of 20 ft^2, what is the efficiency of this solar panel? b. If an average yearly solar irradiance is 150 W/m^2 in Maryland, and the average daylight is 6 hours. How much energy (in kJ) can one solar panel generate daily? c. If we install 18 solar panels on the roof, and the regular electricity rate is $0.16 per kWh, how much you can save in electricity bill per month? d. How long (in years) can we payback the installing of solar if the installing cost of the solar panels is $9, 500?