Physics

Problem

1986B5 (modified) A proposed ocean power plant will utilize the temperature difference between surface seawater and seawater at a depth of 100 meters. Assume the surface temperature is `

25^{\circ}

` Celsius and the temperature at the 100 -meter depth is `

3^{\circ}

` Celsius. a. What is the ideal (Carnot) efficiency of the plant? b. If the plant generates useful energy at the rate of 100 megawatts while operating with the efficiency found in part (a), at what rate is heat given off to the surroundings? The diagram below represents the Carnot cycle for a simple reversible (Carnot) engine in which a fixed amount of gas, originally at pressure `

p_{o}

` and volume `

V_{o}

` follows the path ABCDA. ![](https://storage.googleapis.com/diraq-contents/question-bank/question-images/69444aea0db4/2025_11_20_5d1425108ae7999fb5dag-11.jpg) c. In the chart below, for each part of the cycle indicate with + , -, or 0 whether the heat transferred Q and temperature change `

\Delta \mathrm{T}

` are positive, negative, or zero, respectively. ( Q is positive when heat is added to the gas, and `

\Delta \mathrm{T}

` is positive when the temperature of the gas increases.)

` $Q$ `		` $\Delta T$ `
` $A B$ `
` $B C$ `
` $C D$ `
` $D A$ `

Browse the problem library