# Lamp and tugsten

1. Jan 14, 2007

### Gyroscope

1. The problem statement, all variables and given/known data

$$p_t=p_{20}(1+\alpha (t-20))$$

I have a circuit with a 3,5 V lamp that has a tungsten filament. I can provide to the circuit a variable voltage. How would I find the melting temperature of tungsten?

I know p_20 and alpha and the voltage I provide. And I have an device to measure current too.

Could I just increase voltage until the lamp turns off (which means the tungsten filament melted), measure the current and by means of Ohm's Law I could find the resistance. And then with the initial formula, I could find the temperature to which corresponds this resistance.

Am i right? Sorry my poor English.

Last edited by a moderator: Jan 14, 2007
2. Jan 14, 2007

### Gyroscope

knock, knock...

3. Jan 14, 2007

### brewnog

If you're expecting to have homework problems solved for you within 2 hours, then you're probably at the wrong place.