Question

An inventor tries to sell you his new heat engine that takes in 40 J of heat at 87°C on each cycle, expels 30 J at 27°C, and does 10 J of work. Would it be wise to invest in this engine?

Answer 1

NOT WISE

Step-by-step explanation:

given,

T₁ = 87⁰C = 273 + 87 = 360 K

T₂ = 27⁰C = 273 + 27 = 300 K

work output given = 10 J

efficiency will be equal to :

`\eta = 1 - (T_2)/(T_1)\\\eta = 1 - (300)/(360)\\\eta = 0.166`

output delivery = η ₓ input

= 0.166 ₓ 40

= 6.66 J

hence, the output of new engine is less than the old one so, investing in new engine will not be feasible.