Answer:
14.52 minutes
<u>OR</u>
14 minutes and 31 seconds
Explanation:
Let's first start by mentioning the specific heat of air at constant volume. We consider constant volume and NOT constant pressure because the volume of the room remains constant while pressure may vary.
Specific heat at constant volume at 27°C = 0.718 kJ/kg*K
Initial temperature of room (in kelvin) = 283.15 K
Final temperature (required) of room = 293.15 K
Mass of air in room= volume * density= (4 * 5 * 7) * (1.204 kg/m3) = 168.56kg
Heat required at constant volume: 0.718 * (change in temp) * (mass of air)
Heat required = 0.718 * (293.15 - 283.15) * (168.56) = 1,210.26 kJ
Time taken for temperature rise: heat required / (rate of heat change)
Where rate of heat change = 10000 - 5000 = 5000 kJ/hr
Time taken = 1210.26 / 5000 = 0.24205 hours
Converted to minutes = 0.24205 * 60 = 14.52 minutes
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
Answer:
The maximum length of a surface flaw is 8.24 μm
8.24 μm
Explanation:
Given that:
The modulus of elasticity E = 69 GPa
The specific surface energy 
= 0.3 J/m²
The length of the surface flaw "a" = ??
From the theory of the brittle fracture;
Making a the subject of the formula; we have:
a = 8.24 × 10⁻⁶ m
a = 8.24 μm
Thus; the maximum length of a surface flaw is 8.24 μm
Answer: True
Explanation:
The total opposition to current flow in an AC circuit is known as Impedance.
Answer:
I dont know sorry i in a hurry and i need points so vary sorry
Explanation:
my assistant is due at 9:00 today . Not that you care but
