The electricity that is delivered to our homes from regional generating stations moves over transmission lines that are _____.
2 answers:
Answer:
high voltage and low current
Explanation:
Electricity is transmitted over transmission lines at very high voltages and low current.
The reason for this choice is to minimize the power dissipated along the transmission line. In fact, the dissipated power is given by:
where
Pd is the dissipated power
I is the current
R is the resistance of the cables
V is the voltage
P is the generated power
From the first formula, we see that the dissipated power is proportional to the square of the current, so in order to minimize the loss of power, it is better to use low current. Moreover, from the second formula we see that the dissipated power is inversely proportional to the square of the voltage, so the higher the voltage, the less the power dissipated along the transmission lines.
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Answer:
Option A decreases with increase in altitude
Explanation:
This can be explained as the value of gravitational acceleration, 'g' is not same everywhere.
It has its maximum value at poles of the Earth and minimum on its equator.
Thus a person will weigh more at poles than equator.
This variation is in accordance to:
Thus the gravitational acceleration changes as inverse square of the Radius of the Earth.
Thus as we move away from the Earth's center, gravitational acceleration, g decreases.