Question

A power station burns 75 kilograms of coal per second. Each kg of coal contains 27 million joules of energy.

a. What is the total power of this power station in watts? (watts = joules/second)
b. The power station’s output is 800 million watts. How efficient is this power station?

Answer 1

Step-by-step explanation:

a )

one kg of coal gives energy of 27 x 10⁶ J

75 kg of coal gives energy of 27 x 10⁶ x 75 J

So rate which energy is coming out of coal per second

= 27 x 10⁶ x 75 J

= 2025 x 10⁶ J /s

2025 million watts .

b ) energy output = 800 million watts

efficiency = (800 / 2025) x 100

= 39.5 % .