Why Does a 200V 5W Bulb Glow Brighter on 220V Supply? Current, Voltage, Power Explained

suppose i have bulb of 200v-5watt.It is said in my country the suppy voltage is 220v.when the bulb is connected to the holder will the voltage across it become 200v or remains 220??Will the amount of current consume by that bulb becomes(5/200)??some time at high voltage bulb glows very bright but according to formula our current decreses??Please help me throught it??Small current and brightness how is that possible??

The voltage across the bulb will be 220V.

The current @200V is (P/V) or (5/200) or 25mA. This means that the (hot) resistance of the bulb is R=V/I = 200/0.025 = 8000ohms,

@ 220V, the current will be slightly higher I=E/R = 220/8000 = 27.5mA. P = V * I = 220 * .0275 = 6.05W.

So at 220V the bulb will be approximately 20% brighter.

All forumulas: V=voltage (volts), I=Current (amps), R=Resistance (ohms), P=Power(watts)

Tnx for help.