Answer:
375 KPa
Explanation:
From the question given above, the following data were obtained:
Initial pressure (P₁) = 125 KPa
Initial temperature (T₁) = 300 K
Final temperature (T₂) = 900 K
Final pressure (P₂) =?
The new (i.e final) pressure of the gas can be obtained as follow:
P₁/T₁ = P₂/T₂
125 / 300 = P₂ / 900
Cross multiply
300 × P₂ = 125 × 900
300 × P₂ = 112500
Divide both side by 300
P₂ = 112500 / 300
P₂ = 375 KPa
Thus, the new pressure of the gas is 375 KPa
Answer:

Explanation:
= Energy for defect formation = 1.86 eV
T = Temperature = 
k = Boltzmann constant = 
The fraction of lattice sites that are Schottky defects is given by

The required ratio is
.
Answer:
1) q=18414.93 W
2) C=12920$
Explanation:
Given data:
pipe length L=25m
pipe diameter D=100mm =0.1 m
air temperature
=
=25
°C.....= 298.15k
pipe surface temp
=150
°C.....=423.15k
surface emissivity e= 0.8
boiler efficiency η=0.90
natural gas price Cg=$0.02 per MJ
1) Total heat loss and radiation heat loss combined
q=
q=
б(
^4-
^4)]....... (1)
б=5.67×10^-8 W/m^2K^4 (boltzmann constant)
area A =L.Dπ=25×0.1π=7.85 m^2
putting all these values in eq (1)
q=18414.93 W
2) suppose boiler is operating non stop annual energy loss will be
E=q.t
=18414.93.3600.24.365
=5.81×10^11 J
to find furnace energy consumption
Ef =E/η
=6.46×10^5 MJ
annual cost
C=Cg. Ef
=12920$