Answer:
(a) 
(b) P = 0.816 Watt
Explanation:
(a)
The power radiated from a black body is given by Stefan Boltzman Law:

where,
P = Energy Radiated per Second = ?
σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴
T = Absolute Temperature
So the ratio of power at 250 K to the power at 2000 K is given as:

(b)
Now, for 90% radiator blackbody at 2000 K:

<u>P = 0.816 Watt</u>
Answer:
The current can't 'split down the parallel branch, because the diode is reverse biased so is blocking the flow of current. So basically it's acting as an open circuit. Also when the current flows it wouldn't reduce the currents amount flow through the resistor.
Explanation:
I don’t speak Spanish sorry
Answer:
D= 1999.2 m
Explanation:
Given that
Average velocity ,v= 0.98 m/s
time ,t= 34 min
We know that
1 min = 60 s
That is why
t= 34 x 60 =2040 s
We know that
Displacement = Average velocity x time
D= v t
Now by putting the values in the above equation
D= 0.98 x 2040 m
D= 1999.2 m (eastward)
The direction of the displacement will be towards eastward.
That is why the displacement will be 1999.2 m or we can say that 1.9992 km.
Explanation:
Given that,
Charge 1, 
Charge 2, 
The distance between charges, r = 1.99 m
To find,
The electrostatic force and its nature
Solution,
(a) The electric force between two charges is given by :



(b) As the magnitude of both charges is positive, then the force between charges will be repulsive.
Therefore, this is the required solution.