Physics, 05.09.2019 18:30 Brock2002

Acarnot engine whose low-temperature reservoir is at 19.4°c has an efficiency of 29.7%. by how much should the celsius temperature of the high-temperature reservoir be increased to increase the efficiency to 62.3%?

Answers: 1

Show answers

Answers

Answer from: saltytaetae

The Temperature of the Hot reservoir should be increased by 359.86°C

Explanation:

A Carnot engine is a reversible engine, that means that it can work both as a heat engine and as a refrigerator, it can both use heat from a hot reservoir (part of which later must end up in a cold reservoir) to produce work, or use work to move heat from a cod to a hot reservoir.

The efficiency of a carnot engine working as a heat engine is given by:

$\eta = 1 - \frac{T_C}{T_H}$

were T_H and T_C are the Absolute temperatures of the hot and cold reservoir respectively.

To get the absolute temperature in K from the relative temperature in °C, we must add 273.15 K (the absolute temperature of the freezing point of water at atmospheric pressure)

Thus:

T_C= 19.4+273.15=292.55 K

Now, if we know the Temperature of the cold reservoir, and the engine's efficiency, we can use that information to get T_H as follows:

$\eta = 1 - \frac{T_C}{T_H}\\\eta=0.297\\0.297=1 - \frac{292.55K}{T_H}\\\frac{292.55K}{T_H}=1-0.297=0.703\\T_H=\frac{292.55K}{0.703}=416.14K$

Now, that is the Temperature of the hot reservoir to begin with, but if we want a higher efficency, we need to increase T_H until $\eta=0.623$ .

To find out what value T_H has to reach, we repeat the same calculation as before, except now $\eta= 0.623$

$0.623=1 - \frac{292.55K}{T_H}\\\frac{292.55K}{T_H}=1-0.623=0.377\\T_H=\frac{292.55K}{0.377}=776.00K$

So T_H has increased from 416.14K to 776 K , that means an increase in temperature of : $\DeltaT= 776K-416.14K=359.86K$

This increment of 359.86K is also an increment of 359.86°C, because increments are relative measures of temperature.

Answer from: Jasten

359.67°C or 359 K

Explanation:

Case I:

T2 = 19.4°C = 19.4 + 273 = 292.4 K

η = 29.7 % = 0.297

Let T1 be the temperature of hot reservoir.

By using the formula for the efficiency of Carnot's heat engine

$\eta =1-\frac{T_{2}}{T_{1}}$

$0.297 =1-\frac{292.4}{T_{1}}$

$0.703=\frac{292.4}{T_{1}}$

T1 = 415.93 k

Case II:

T2 = 19.4°C = 19.4 + 273 = 292.4 K

η = 62.3 % = 0.623

Let T'1 be the temperature of hot reservoir.

By using the formula for the efficiency of Carnot's heat engine

$\eta =1-\frac{T_{2}}{T_{1}}$

$0.0.623 =1-\frac{292.4}{T'_{1}}$

$0.377=\frac{292.4}{T'_{1}}$

T'1 = 775.6 k

Incraese in the temperature of hot reservoir

= T'1 - T1 = 775.6 - 415.93 = 359.67°C or 359 k

Answer from: Quest

answer: 0.20

explanation: this can only be the answew because all the other measuremnets are not close

Answer from: Quest

The duration of a photographic flash is related to an rc time constantly

Another question on Physics

Physics, 21.06.2019 22:50

Calculate the heat capacity per object when the total energy is 4 quanta. (think of this in terms of increasing from 3.5 quanta of energy in the system to 4.5 quanta of energy in the system, if that were possible.) c4 = __ j/k/object

Answers: 2

Answer

Physics, 22.06.2019 00:00

What should the power status of a circuit be when measuring resistance with an ohmmeter?

Answers: 2

Answer

Physics, 22.06.2019 05:00

In a stagnant pool of water, a crayfish may spend much of its time lying with one side of its carapace near the surface of the water. in this position, it will move the walking legs on that side in a rhythmic back-and-forth motion. explain the likely function of this behavior.

Answers: 1

Answer

Physics, 22.06.2019 09:40

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)

Answers: 1

Answer

You know the right answer?

Acarnot engine whose low-temperature reservoir is at 19.4°c has an efficiency of 29.7%. by how much...

Questions