Because the tip of the moon's shadow ... the area of "totality" ... is never more than a couple hundred miles across, It never covers a single place for more than 7 minutes, and can never stay on the Earth's surface for more than a few hours altogether during one eclipse.
If you're not inside that small area, you don't see a total eclipse.
To answer that question, we don't care what the highest and lowest
levels of the wave are, or how far apart they are. We only need to be
able to identify the highest point on the wave, and keep track of how
often those pass by us.
You said it takes 4 seconds for a complete wave to pass by.
Through the sheer power of intellect, I'm able to take that information
and calculate that 1/4 of the wave passes by in 1 second.
There's your frequency . . . 1/4 per second, or 0.25 Hz.
Answer:
R = 35.27 Ohms
Explanation:
Given the following data;
Voltage = 230V
Power = 1500W
To find the resistance, R;
Power = V²/R
Where:
V is the voltage measured in volts.
R is the resistance measured in ohms.
Substituting into the equation, we have;
1500 = 230²/R
Cross-multiplying, we have;
1500R = 52900
R = 52900/1500
R = 35.27 Ohms.
Therefore, the resistance which the heating element needs to have is 35.27 Ohms.