An inventor claims to have developed a refrigerator that at steady state requires a net power input of 1.1 horsepower to remove
1 answer:
Answer:
The inventor's claim is false in the sense that no thermal machine can violate the first thermodynamic law.
Explanation:
The inventor's claim could not be possible as no thermal machine can transfer more heat than the input work consumed. If we expose the thermal efficiency:
Where Q and W both must be in the same power unit, so we will convert the remove heat from BTU/hr to hp:
Therefore by comparing, we notice that the removing heat of 4.75 hp is large than the delivered work of 1.11 hp. By evaluating the efficiency:
[tex]n=4.75 hp / 1.1 hp = 4.3 > 1[/tex]
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Answer:
In Btu:
Q=0.001390 Btu.
In Joule:
Q=1.467 J
Part B:
Temperature at midpoint=274.866 C
Explanation:
Thermal Conductivity=k=30 (Btu/hr)/(ft ⋅ °F)=
Thermal Conductivity is SI units:
Length=20 cm=0.2 m= (20*0.0328) ft=0.656 ft
Radius=4/2=2 mm =0.002 m=(0.002*3.28)ft=0.00656 ft
T_1=500 C=932 F
T_2=50 C= 122 F
Part A:
In Joules (J)
Heat Q is:
In Btu:
Heat Q is:
PArt B:
At midpoint Length=L/2=0.1 m
On rearranging:
Answer:
Answer is Option (e) - None of these
Explanation:
The step by step derivation from the fourier's law of heat conduction is as shown in the attachment below.
Where K = thermal conductivity
