$$\textbf{Power Rating of an Electrical Appliance:}$$
$$\bullet$$ Every electrical appliance has a power rating which tells how much electricity it needs to work. This is usually given in watts (W) or kilowatts (kW) (1000W = 1kW).
$$\bullet$$ Power rating is also accompanied by the maximum working voltage, an appliance needs to work with its full capacity.
$$\textbf{Calculation of Resistance of an Electrical Appliance:}$$
$$\bullet$$ The relationship between Power Rating, Working Voltage and Resistance of an electrical appliance is $$P=\dfrac{V^2}{R}$$.
$$\therefore$$ $$R=\dfrac{V^2}{P}$$
$$\textbf{Calculation of Safe Limit of Current:}$$
As we know, $$P = VI$$,
$$\therefore$$ $$I=\dfrac{P}{V}$$
$$\bullet$$ This current is the safe limit of an electrical appliance, if it is operated across maximum operating voltage $$V$$.