Answer:
32%
Step-by-step explanation:
For a heat engine, efficiency is work out divided by heat in:
η = Wₒ / Qᵢ
Since energy is balanced, heat in is the sum of work out and heat out:
Qᵢ = Wₒ + Qₒ
Therefore:
η = Wₒ / (Wₒ + Qₒ)
Given Wₒ = 710 J and Qₒ = 1480 J:
η = 710 / (710 + 1480)
η = 0.32
The thermal efficiency is 32%.