How much coal does it take to power a light bulb?

Given:

\[ 1 Watt = 1 \frac{Joule}{Second} \]

For a 100 Watt Bulb:

\[ \require{cancel} (100 \cancel{Watt})\left(1 \frac{\frac{Joule}{Second}}{\cancel{Watt}}\right) = 100 \frac{Joule}{Second} \]

For One Minute:

\[ \left(100 \frac{Joule}{\cancel{Second}}\right) \left(60 \frac{\cancel{Second}}{Minute}\right) = 6{,}000 \frac{Joule}{Minute} \]

For One Hour:

\[ \left(6 \times 10^3 \frac{Joule}{\cancel{Minute}}\right)\left(60 \frac{\cancel{Minute}}{Hour}\right) = 3.6 \times 10^5 \frac{Joule}{Hour} \]

For One Day:

\[ \left(3.6 \times 10^5 \frac{Joule}{\cancel{Hour}}\right)\left(24 \frac{\cancel{Hour}}{Day}\right) = 8.64 \times 10^6 \frac{Joule}{Day} \]

bulb = 100 # Watt (Joule/Second)
per_minute = bulb * 60 # Second/Minute
per_hour = per_minute * 60 # Minute/Hour
per_day = per_hour * 24 # Hour/Day
print(f"A 100 Watt Light bulb uses {per_day:0.2e} Joules per day.")

A 100 Watt Light bulb uses 8.64e+06 Joules per day.

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