Complete Question
Analyze the boundary work done during the process having a rigid tank contains air at 500 kPa and 150°C. As a result of heat transfer to the surroundings, the temperature and pressure inside the tank drop to 65°C and 400 kPa, respectively.
Determine the boundary work done during this process and heat Lose
Answer:
a) [tex]W=0[/tex]
b) [tex]dQ=-61.03KJ/kg[/tex]
Explanation:
From the question we are told that:
Pressure of air [tex]P_1=500kpa[/tex]
Temperature of Air [tex]T_2=150°C[/tex]
Pressure drop [tex]P_2=400kpa[/tex]
Temperature of drop [tex]T_2=65 \textdegree C[/tex]
Generally the Constant Volume Process is mathematically given by
[tex]V_1=V_2=V[/tex]
Therefore
a)
Generally the equation for boundary work w is mathematically given by
[tex]W=pdv[/tex]
[tex]W=P(V_2-V_1)[/tex]
[tex]W=P(V_V)[/tex]
[tex]W=0KJ[/tex]
b)
Generally the equation for Heat Change is mathematically given by
[tex]dQ=dU+dW[/tex]
[tex]dQ=dU[/tex]
[tex]dQ=C_v(T_2-T_1)[/tex]
Where
C_v=Specific Heat capacity of Air
[tex]C_v=0.718 kJ/kg K[/tex]
[tex]dQ=0.718(338-423)[/tex]
[tex]dQ=-61.03KJ/kg[/tex]
The output side of an ideal transformer has 35 turns, and supplies 2.0 A to a 24-W device. Ifthe input is a standard wall outlet, calculate the number of turns on the input side, and the currentdrawn from the outlet.
Answer:
The current drawn from the outlet is 0.2 A
The number of turns on the input side is 350 turns
Explanation:
Given;
number of turns of the secondary coil, Ns = 35 turns
the output current, [tex]I_s[/tex] = 2 A
power supplied, [tex]P_s[/tex] = 24 W
the standard wall outlet in most homes = 120 V = input voltage
For an ideal transformer; output power = input power
the current drawn from the outlet is calculated;
[tex]I_pV_p = P_s\\\\I_p = \frac{P_s}{V_p} = \frac{24}{120} = 0.2 \ A[/tex]
The number of turns on the input side is calculated as;
[tex]\frac{N_p}{N_s} = \frac{I_s}{I_p} \\\\N_p = \frac{N_sI_s}{I_p} \\\\N_p = \frac{35 \times 2}{0.2} \\\\N_p = 350 \ turns[/tex]