A 20 watt light bulb is left burning inside a refrigerator operating on a reverse Carnot cycle. If the refrigerator also draws 2
1 answer:
Explanation:
Given that,
Power drawn by the refrigerator = 20 watt
Power of burning light inside = 20 watt
Room temperature = 27°C
We need to calculate the temperature
Using formula of coefficient of refrigerator
Put the value into the formula
is less than
Therefore, refrigerator cools its interior below room temperature while the bulb is on.
Hence, This is the required solution.
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Answer:
Having a bigger angle above the horizontal
Explanation:
Applying the energy conservation theorem:
The kinetic energy is reduced because of the work done by the friction force.
The friction force is given by:
so the friction force depends on the Normal force, because the slide has an angle the normal force is given by:
So when the angle of the slide is bigger, the friction force decreases, for example:
for 45 degrees:
for 75 degrees:
as you can see if the angle is bigger above the horizontal, the friction force is reduced and so the work done by that force. We didn't have to change the height of the slide, so the potential gravitational energy remains the same.
Assuming north as positive direction, the initial and final velocities of the ball are:
(with negative sign since it is due south)
the time taken is
, so the average acceleration of the ball is given by
And the positive sign tells us the direction of the acceleration is north.
the time taken is
And the positive sign tells us the direction of the acceleration is north.
Answer:
You will need 450 cells (3 cm each) to meet the voltage/current requirement.
The panel must be 3 cells in one side, by 150 cell in another side. 1350 cm^2 or 0.135 m^2. They must be connected 3 in row in parallel (to add current), then each of the former group must be connected in series to meet the voltage, so it would be 150 rows of connected in series.
The panel can be optimized using a voltage inverter, to convert current to voltage. In this way, less cells can be used achieving the same output specs.
Explanation:
To meet the voltage:
120 [v] required voltage
0.8 [v] voltage of each cell
So we need 150 cells in series for the voltage.
To meet the current
1.0 [A] Required current
350[mA]=0.35[A] cell current
1/0.35=3 cell So we need 3 cells in parallel to add the currents and meet the requirement.
See the attached figure
