Answer:
Option C (80 ohms) is the right answer.
Explanation:
The given values are:
Current,
I = 1.5 A
Voltage,
V = I20 V
As we know,
⇒
or,
The resistance will be:
⇒
On substituting the values, we get
⇒
⇒
Answer:
Ts = 413.66 K
Explanation:
given data
temperature = 20°C
velocity = 10 m/s
diameter = 5 mm
surface emissivity = 0.95
surrounding temperature = 20°C
heat flux dissipated = 17000 W/m²
to find out
surface temperature
solution
we know that here properties of air at 70°C
k = 0.02881 W/m.K
v = 1.995 × m²/s
Pr = 0.7177
we find here reynolds no for air flow that is
Re =
Re =
Re = 2506
now we use churchill and bernstein relation for nusselt no
Nu = = 0.3 +
h = 0.3 +
h = 148.3 W/m².K
so
q conv = h∈(Ts- T∞ )
17000 = 148.3 ( 0.95) ( Ts - (20 + 273 ))
Ts = 413.66 K
Answer:
60 rpm
Explanation:
At t = 0,
Angular speed = 0
At t = 10 sec
Angular speed = 20/10 = 2 rev/s
Average speed = (2 - 0)/2 = 1 rev/s
= 1 x 60 = 60 rpm
Answer:
h=27.15 KJ/kg
Explanation:
We know that ,Enthalpy of perfect gas depends only on temperature it did not depends on the volume and pressure.But on the other hand enthalpy of real gas depends on the temperature and pressure.
So specific enthalpy(h) is given as follows
For oxygen
From above
So
h=27.15 KJ/kg