How to find the resistance of light bulb?

How to find the resistance of light bulb?

Because P = IV, v = IR
So r = V ^ 2 / P
R: The resistance of the bulb, unit: Ohm, indicated by the symbol Ω; this resistance is the resistance in normal operation, and it is normal to measure it with a multimeter when it is cold
5: Rated working voltage of bulb, unit: V, indicated by symbol V;
P: The rated power of a light bulb, in watts, is indicated by the symbol W. in everyday language, Watts are called branch lights, that is to say, a lamp with 40 lights is 40W
By the way, P = IV is electrical power, v = IR, Ohm's law
Ohm's law can also be applied to the calculation of the other parameter between the current, voltage and inductance (capacitance) reactance of capacitive load and inductive load in AC circuit. Because of the phase problem, the electric power is not suitable

Is a light bulb pure resistance? Please explain it carefully,

Pure resistance circuit means that all electric energy is converted into heat energy, but not into other forms of energy resistor. The electric energy of electric lamp is basically converted into heat energy, and the energy converted into light energy is very small, so it can be regarded as pure resistance