Question

1) A coal fired power plant produces 1.00x10^14 J per day by burning coal. If the efficiency is 40.0%, 
how much work does the turbines do?

2) How much energy is lost to the environment (as heat)?

3) If 1 kg of coal can produce 2.5x10^6 J, and 1 kg of coal produces 3.67 kg of CO2, how much CO2 is produced
in a year from this plant?

4) If there are 1000 such power plants worldwide, how long will it take these plants to double the 
amount of CO2 in the atmosphere? You may want to ask Google about how much CO2 there is in the atmosphere.

Answer 1

1) Qin = 1.00*10^14 J

e = 40%

= 0.40

now use, e = W/Qin

==> W = Qin*e

= 1.00*10^14*0.4

= 4.00*10^13 J <<<<<<<<<--------------------Answer

2) Energy lost to the environment,

Q_out = Qin - W

= 1.00*10^14 - 4.00*10^13

= 6.00*10^13 J <<<<<<<<<--------------------Answer

3) the mass of the coal used in one day = 1*10^14/(2.5*10^6)

= 4.00*10^7 kg

mass of the coal used in one year = 365*4*10^7

= 1.46*10^10 kg

CO2 produced in one year = 1.46*10^10*3.67

= 5.36*10^10 kg <<<<<<<<<--------------------Answer

4) total present mass of CO2 = 2.996*10^15 kg

time taken to double CO2 = 2.996*10^15/(1000*5.36*10^10)

= 55.9 years <<<<<<<<<--------------------Answer