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 ofPhysics (Single Science)Electricity, energy and waves
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
