2nd law of thermodynamics

2nd law of thermodynamics

Multiple Choice

A heat engine produces 3 000 J of heat during the

combustion of fuel and releases 2 000 J of heat from

its exhaust. What is the efficiency of this engine?

• 13%

• 23%

• 33%

• 43%

Fill in the Blanks

A heat engine of η=0.3, loses 4900 J heat during one cycle. What is the work done by the engine in one cycle?

J

Fill in the Blanks

A steam power plant burns 50 tons of coal every hour.

The useful power output of the plant is 130 MW

(megawatts =10⁶ watts). What is the efficiency of this

plant? (Take q_coal= 30 MJ/kg)