Answer:

Explanation:
speed of motor (N)=1500 rpm
power=4 hp =
=2.9828 KW
service factor(k)= 2.75
now,


torque rating

Answer:
The total hole mobility is 41.67 cm²/V s
Explanation:
Data given by the exercise:
hole mobility due to lattice scattering = ul = 50 cm²/V s
hole mobility due to ionized impurity = ui = 250 cm²/V s
The total mobility is equal:

Answer:
(a) The power input to the compressor: 
(b) The volume flow rate of the refrigerant at the compressor inlet: 
Explanation:
(a)
We need to check the values of enthalpy (as we have an open system) for both states, being the inlet, state 1 and the outlet, state 2. We will know these values by checking the vapor charts of R134a, I used the ones found in Thermodynamics of Cengel, 7th edition.
Then, our values are:

Now we proceed to know the work with the following expression:

Now we replace values and our result is:

(b)
To know the volume rate at the compressor inlet, we need to know the specific volume in that phase, as we have that is saturated and at -24°C, we can read our table:

With our specific volume and the mass rate, we can calculate the volume rate:

Answer:
The pressure inside the cooker is 1.0804 atm.
Explanation:
Boiling occurs when the vapor pressure becomes equal to atmospheric pressure.
<u>For water, At standard conditions (Pressure = 1 atm) boiling occurs at 373.15 K.</u>
So, Standard conditions:
T₁ = 373.15 K
P₁ = 1 atm
Given ,
The water boils at Temperature = 130 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So, the temperature, T₂ = (130 + 273.15) K = 403.15 K
To find pressure inside the cooker (P₂) :
<u>Applying Amontons's Law as:</u>

So,



<u>Thus, The pressure inside the cooker is 1.0804 atm.</u>
Answer:
Q' = 8 KW.h
Q'=28800 KJ
Explanation:
Given that
Heat Q= 4 KW
time ,t = 2 hours
The amount of energy used in KWh given as
Q ' = Q x t
Q' = 4 x 2 KW.h
Q' = 8 KW.h
We know that
1 h = 60 min = 60 x 60 s = 3600 s
We know that W = 1 J/s
The amount of energy used in KJ given as
Q' = 8 x 3600 = 28800 KJ
Therefore
Q' = 8 KW.h
Q'=28800 KJ