You can use this online calculator to check the solution of problems for electric power and electrical work. To use it, enter known values and leave unknown values blank. If there are enough data, hit the "Calculate" button, and the calculator finds all unknowns.
Sample problem: The crane consumes a current of 40A from an electrical network with a voltage of 380V. The crane took 3.5 minutes to lift the concrete slab. Find the work that the crane did.
To get the solution, enter 40 into the "Current" field, then enter 380 into the "Voltage" field, then 3.5 into the "Time" field, switching time units to "minutes". After that, click the "Calculate" button. The calculator outputs work in Joules and power in Watts and resistance in Ohms (because it can). Below you can find formulas used for calculations below the calculator.
Electrical work and power of electric current
Electrical work is the work done on an electric charge by the electric force. Electric work can be found as the multiplication of quantity of transferred electric charge by electric potential or voltage between endpoints.
From the other side, the electric current is the rate of flow of electric charge past a point over time
Hence, electrical work can be expressed as a multiplication of current, voltage, and time
This, by the way, gives us that 1Joule = 1Volt·1Amper·1second
Since Ohm's law gives us this equation
We can also express electrical work like this:
Since power is the rate of doing work per unit of time, we can express electric power as