Engineers connect components in electrical circuits in series or parallel to make a range of useful circuits. We can calculate the voltage, current and resistance in these circuits.
Part of Physics (Single Science)Electricity, energy and waves
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Power is the energy transferred per unit time.
\(\text{energy}={\text{power}}\times{\text{time}}\)
\(\text{E}={\text{Pt}}\)
or
\(\text{power =}~\frac{\text{energy}}{\text{time}}\)
Power is measured in watts (W), energy in joules (J) and time in seconds (s).
1 W = 1 J/s
(1 watt is 1 joule per second.)
Electrical power can be calculated using the equation.
\(\text{power}={\text{voltage}}\times{\text{current}}\)
P = V × I
Remember, V = I × R, so by substituting for V, we can write the equation as
P = I × I × R
This can also be written as P = I2 R.
Calculate the power dissipatedclosedissipateSpread out into the surroundings. by a 33 Ω resistor when a current of 2 A flows through it.
P = I2
R = 22 × 33
= 132 W