A solar panel has an efficiency of 15%. How much solar power is necessary to produce 300 watts of useful power?
Since the solar panel has an efficiency of 15%, this means that only 15% of the solar power that hits the panel can be converted into useful power. Therefore, to calculate how much solar power is necessary to produce 300 watts of useful power, we need to divide 300 watts by the efficiency, which is 0.15, since 15% is equivalent to 0.15. By doing this calculation, we get:
300 watts / 0.15 = 2000 watts
Therefore, 2000 watts of solar power is necessary to produce 300 watts of useful power.