contestada

When a certain ideal engine performs 2000 kJ of work, 4750 kJ of heat flows out of the engine at 275°C. (a) How much heat flows into the engine? (b) What is the efficiency of the engine? (c) At what temperature does heat flow into the engine?

Respuesta :

Answer:

a) Qh= 6750 kJ

b) e = 0.296

c) [tex]T_H[/tex] = 390.625° C

Explanation:

Given:

Work done, W = 2000 kJ

Heat flow, Q = 4750 kJ

Temperature at which heat flows out, [tex]T_c[/tex] = 275° C

a) Now, the heat flow through the engine (Qh)

Qh = W + Q

or

Qh = 2000 + 4750

or

Qh= 6750 kJ

b) The efficiency (e) is given as:

[tex]e=\frac{W}{Q_h}[/tex]

on substituting the values, we get

[tex]e=\frac{2000}{6750}[/tex]

or

e = 0.296

c) [tex]e=1-\frac{T_c}{T_H}[/tex]

where,

[tex]T_H[/tex] is the temperature at which heat flow

on substituting the values, we get

[tex]0.296=1-\frac{275}{T_H}[/tex]

or

[tex]T_H[/tex] = 390.625° C

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