We will first calculate the power by using the given values of current and resistance. This can be done by using the formula:
`P = I^(2) xx R`
Here, Current, `I = 5` amperes
And, Resistance `R = 2` ohms
So, Power, `P = (5)^(2) xx 2`
`= 25 xx 2`
= 50 watts
`= (50)/(1000)` kilowatts
Thus, Power, `P = 0.05 kW` ......(1)
And, Time, `t = 30` minutes
`= (30)/(60)` hours
`= (1)/(2)` hours
`= 0.5` hours ...(2)
Now, Energy, `E = P xx t`
`=0.05 xx 0.5`
Energy, `E = 0.025 kWh`
In the above given sample problems, we have calculated the electrical energy in the commercial unit of 'kilowatt-hour'. Please calculate the energy in 'joules' yourself.
