Electric circuits are used to transfer energy from one place to another. Whenever there is a current in a circuit energy is transferred from the power source to the component. Opening a switch/turning off the power source will result in no current as no energy is transferred.
Power is the rate of energy transfer between each electrical component. It is measured in watts and can be calculated using the equation:
Power is the rate of energy transfer between each electrical component. It is measured in watts and can be calculated using the equation:
P=IV
Using V=IR we can get two more equations for power...
P= I2R and P=V2/R
The derivation:
P=W/t
W=VQ
P=(VQ)/t
I=Q/t
P=IV
If we substitute P=W/t (--> W=Pt) into P=IV we get W=VIt. This is an equation for energy transferred.
Last bit in this section (yayy). We just need to know about the kilowatt hour and how to calculate the cost of energy...
The energy transferred to a device depends on how long the device is used for and the power of the device.
One joule is a very minuscule amount so instead electricity bill people use the kilowatt hour (kWh). This is the energy transferred by a device with a power of 1kW operating for a time of 1 hour. It is equal to 3.6MJ.
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