Power Rating of A Resistor

The power rating of a resistor is the measure of the heat dissipated by a resistor from voltage .

If more voltage or current is supplied to a resistor , than the given threshold , the amount of energy converted to heat by a resistor , will increase, which will burn the resistor

Find the maximum current that can be passed from a resistor of 20 Watts having value of 20 K Ω.

20 watts means that the value of power across resistor should never increase 20 watts. It should always be less than 20 Watts