How much​ energy, in​ joules, can the solar panel produce each​ day? Give the value in millions of joules per day.

Question

Solar (photovoltaic) cells convert sunlight directly into electricity. If solar cells were 100% efficient, they would generate about 1000 watts of power per square meter of surface area when exposed to direct sunlight. With lower efficiency, they generate proportionally less power. For example, 10% efficient cells generate 100 watts of power in direct sunlight.
Suppose a 1-square-meter panel of solar cells has an efficiency of 9090% and receives the equivalent of 33 hours of direct sunlight per day. How much energy, in joules, can it produce each day? What average power, in watts, does the panel produce?

Answer 1

Some of the numbers in the problem statement appear to be doubled, like 9090% and 33 hours.  I assume you meant 90% and 3 hours.

 

P/A = power per m² at 100% efficiency = 1000 W/m² = 1000 J/(m²s)

η = efficiency in decimal form = 0.90

A = surface area of photovoltaic cells = 1 m²

t = seconds of direct sunlight each day = 3(3600) s = 10800 s 

E = energy produced each day

 

E = η(P/A)At = 0.90 [1000 J/(m²s)] (1 m²) (10800 s) = 9,720,000 J = 9.72 MJ

 

Average power in watts:

 

<P> = η(P/A)A = 0.90 [1000 J/(m²s)] (1 m²) = 900 J/s = 900 Watts