KS 4 PVI Boardworks Ltd 2003 PIV We
KS 4 P=VI © Boardworks Ltd 2003
P=IV We can express the relationship between current, voltage and power mathematically using the equation: Power = Current x Voltage P=IV Voltage measured in Volts (V) Current measured in Amps (A) Power measured in Watts (W) © Boardworks Ltd 2003
Formula triangles help you to rearrange formula, the triangle for the Power Law is shown below: Whatever quantity you are trying to find cover it up and it will leave you with the calculation required. So if you were trying to find current, I…. . …you would cover I up… …and you are left with the sum… P I V I = P V x © Boardworks Ltd 2003
Power calculations If you have a filament bulb and it has a potential difference of 200 V across it and a current of 0. 2 A running through it. At what power is the bulb operating at? P = IV P = 0. 2 A x 200 V P = 40 W © Boardworks Ltd 2003
Power calculations If you have a filament bulb and it operates at a power of 60 W and it has a potential difference of 240 V across it, what is the current running through the bulb? P = IV I = P/V I = 60 W / 240 V I = 0. 25 A © Boardworks Ltd 2003
k. V, k. J, k. W 1 k. V = 1000 V 1 k. J = 1000 J 1 k. W = 1000 W How many Volts in 6 k. V? 6 000 V _____ How many Joules in 12. 3 k. J? 12 300 J _____ How many Watts in 0. 6 k. W? 600 _____ W © Boardworks Ltd 2003
k. V, k. J, k. W 1 k. V = 1000 V 1 k. J = 1000 J 1 k. W = 1000 W How many kilo. Volts in 9 000 V? 9. 0 _____ k. V 23. 5 How many kilo. Joules in 23 500 J? _____ k. J How many kilo. Watts in 325 W? 0. 325 k. W _____ © Boardworks Ltd 2003
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