Given:
Temperature of water, = =273 +(-6) =267 K
Temperature surrounding refrigerator, = =273 + 21 =294 K
Specific heat given for water, = 4.19 KJ/kg/K
Specific heat given for ice, = 2.1 KJ/kg/K
Latent heat of fusion, = 335KJ/kg
Solution:
Coefficient of Performance (COP) for refrigerator is given by:
Max =
= = 9.89
Coefficient of Performance (COP) for heat pump is given by:
Max = = 10.89
Answer:
209.55 ft
Explanation:
Given Data:
Benchmark:
Reduced Level or Elevation = 210.50
Height of Instrument = Reduced Level + Back sight Reading
Height of Instrument = 210.50 + 3.57 = 214.07 ft
Turning Point:
Back sight Reading = 2.91 ft
Fore Sight Reading = 4.52
Reduced Level or Elevation of Turning Point = Height of Instrument – fore sight Reading
Reduced Level or Elevation of Turning Point = 214.07 – 4.52 = 209.55 ft
Height of Instrument at Turning Point = Reduced Level + Back sight Reading
Height of Instrument at Turning Point = 209.55 + 2.91 = 212.46 ft
Answer:
Hello your question is incomplete below is the complete question
Electronic components are often mounted with good heat conduction paths to a finned aluminum base plate, which is exposed to a stream of cooling air from a fan. The sum of the mass times specific heat products for a base plate and components is 5000 J/K, and the effective heat transfer coefficient times surface area product is 10 W/K. The initial temperature of the plate and the cooling air temperature are 295 K when 300 W of power are switched on. 1) Find the plate temperature after 10 minutes.
answer ; 311.36 k
Explanation:
Given data :
sum of mass * specific heat products for a base plate and components ( Mcp )
= 5000 J/K
effective heat transfer coefficient * surface area ( hA ) = 10 W/K
Initial temperature of plate and cooling air temperature( Tc ) = 295 k
power ( Q = W ) = 300 W
a) Determine plate temperature after 10 minutes
10 mins = 600 secs ( t )
heat supplied = change in temp + heat loss
Q * t = mCp ( ΔT ) + hA ( ΔT ) t
300*600 = 5000 * ( T -295 ) + 10 ( T -295 ) * 600
therefore ; T - 295 = 16.363
T = 311.36 K
Explanation:
A.
H = Aeσ^4
Using the stefan Boltzmann law
When we differentiate
dH/dT = 4AeσT³
dH/dT = 4(0.15)(0.9)(5.67)(10^-8)(650)³
= 8.4085
Exact error = 8.4085x20
= 168.17
H(650) = 0.15(0.9)(5.67)(10^-8)(650)⁴
= 1366.376watts
B.
Verifying values
H(T+ΔT) = 0.15(0.9)(5.67)(10)^-8(670)⁴
= 1542.468
H(T+ΔT) = 0.15(0.9)(5.67)(10^-8)(630)⁴
= 1205.8104
Error = 1542.468-1205.8104/2
= 168.329
ΔT = 40
H(T+ΔT) = 0.15(0.9)(5.67)(10)^-8(690)⁴
= 1735.05
H(T-ΔT) = 0.15(0.9)(5.67)(10^-8)(610)⁴
= 1735.05-1059.83/2
= 675.22/2
= 337.61