/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 33 The coefficient of performance o... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 21: Q. 33 (page 596)

The coefficient of performance of a refrigerator is5.0. The compressor uses10Jof energy per cycle.

a. How much heat energy is exhausted per cycle

b. If the hot-reservoir temperature is27掳C, what is the lowest possible temperature inC鈭�of the cold reservoir?

Short Answer

Expert verified

a.Heat energy is exhausted per cycle is60J.

b.Lowest possible temperatureTcis-23掳C.

Step by step solution

01

Calculation for heat energy is exhausted per cycle  (part a)

a.

As a result of the first law that was applied to refrigerators, we now have

Qc=Qh+W

K=QcW鈬�Qc=KW

Substituting this we get,

Qc=Qh-W=W(K+1)

Qh=10路(5+1)=60J

02

Calculation for lowest possible temperature (part b)

b.

When the coefficient of performance is that of a Carnot refrigerator, the lowest value of the temperature of the cold reservoir is reached.

That is,

K=TcTh-Tc=ThTh-Tc-1

The value of the lower temperature can be separated as follows:

Th=(K+1)Th-Tc鈬�-ThK=-(K+1)Tc

Tc=ThKK+1

The minimum temperature ,

Tc=55+1路(273+27)=250K

In degrees centigrade,

Tc=-23掳C

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A heat engine with a thermal efficiency of 40%does 100Jof work per cycle. How much heat is (a) extracted from the hot reservoir and (b) exhausted to the cold reservoir per cycle?

Do the energy-transfer diagrams inFIGUREQ21.9represent possible refrigerators? If not, what is wrong?

A refrigerator using helium gas operates on the reversed cycle shown in FIGURE. What are the refrigerator鈥檚 (a) coefficient of performance and (b) power input if it operates at 60cycles per second?

The first and second laws of thermodynamics are sometimes stated as "You can't win" and "You can't even break even." Do these sayings accurately characterize the laws of thermodynamics as applied to heat engines? Why or why not?

The FIGURE shows the Diesel cycle. It is similar to the Otto cycle (see Problem), but there are two important differences. First, the fuel is not admitted until the air is fully compressed at point 2. Because of the high temperature at the end of adiabatic compression, the fuel begins to burn spontaneously. (There are no spark plugs in a diesel engine!) Second, combustion takes place more slowly, with fuel continuing to be injected. This makes the ignition stage a constant-pressure process. The cycle shown, for one cylinder of a diesel engine, has a displacement localid="1650278379201" Vmax-Vminof localid="1650278390412" 1000cm3and a compression ratio localid="1650278397535" r=Vmax/Vmin=21These are typical values for a diesel truck. The engine operates with intake air localid="1650278425123" (纬=1.40)at localid="1650278430754" 25掳Cand localid="1650278435051" 1.0atmpressure. The quantity of fuel injected into the cylinder has a heat of combustion of localid="1650278440305" 1000J.

a. Find p, V, and Tat each of the four corners of the cycle. Display your results in a table.

b. What is the network done by the cylinder during one full cycle?

c. What is the thermal efficiency of this engine?

d. What is the power output in kW and horsepower (1hp=746W)of an eight-cylinder diesel engine running at 2400rpm?
See all solutions

Recommended explanations on Physics Textbooks

Space Physics

Read Explanation

Famous Physicists

Read Explanation

Atoms and Radioactivity

Read Explanation

Medical Physics

Read Explanation

Measurements

Read Explanation

Waves Physics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.