Question

What determines the rate at which energy is delivered by a current.

Answer 1

We can start by identifying the rate at which energy is delivered by a current. We can see that power is defined as the rate at which energy is delivered by a current. Then we are asked to state the factors that determine the power of an appliance. We can simply state the factors that power is dependent on, thus leading us to the required solution.
The formula for finding the power of an appliance is given by $P = {I^2}R$
Where $R$ is the resistance of the material used
$I$ is the current flowing through the appliance.

Complete answer:
Let us start to attempt this question by stating the physical quantity that is defined as the rate at which energy is delivered by a current.
Now that we have a term for the physical quantity defined by the statement given in the question, we can move onto writing down a suitable formula for the power in an appliance.
The formula for finding the power of an appliance is given by $P = {I^2}R$
From the above equation, we can say that power directly depends on two factors, that is, the current through the appliance and the resistance of the material used in the appliance.

Note:
The unit of power is watt denoted by the capital letter “W”. Power can also be defined as the rate of doing work. From this definition we can say that one watt is the power supplied by an energy of one joule in one second.
$P = \dfrac{W}{t}$
Where $W$ is the work done
$t$ is the time taken to do the work.