Solve Ohms Law: Resistance & Resistivity, 30W 6A Bulb

AI Thread Summary
Resistance measures a material's ability to conduct electric charge, while resistivity is a material-specific constant that helps calculate resistance. The discussion centers on a 30W, 6A bulb, where the filament's resistance at 37 degrees Celsius is 0.15 ohms. The relationship between resistance and temperature is highlighted, indicating that resistance is directly proportional to absolute temperature. Participants suggest using the known resistance values at different temperatures to solve for the working temperature of the filament. The conversation emphasizes understanding the linear relationship between resistance and temperature as a key to solving the problem.
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Homework Statement



Define resistance and resistivity? A 30W, 6A bulb has a filiment which is directly prortional to the absolute temperature? At 37 degrees celcius the reisitance of the fimament is 015ohms. What is the working temperature of the filament?


Homework Equations



None given. But from my attempt I have used V=IR, P=IV.



The Attempt at a Solution



Resistance is a measure of a materials ability to pass charge. Reisistivity is a constant for each material which allows us to calculate the resitance, thus it is the ability for a material to pass current.

Ok so I worked out the current using P=IV
getting: I=6A

I then used this to work out the resistacne using V=IR
getring R=1.2ohms.

Im stuck here and don't know what to do, can someone please give me some hints or a rough idea about how to go about solving this problem? thanks
 
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> A 30W, 6A bulb has a filiment which is directly prortional to the absolute temperature?

This question should be a statement and has got something missing -- probably that the resistance is directly prortional to the absolute temperature. Please verify.
 
sorry. its the resistivity which is directly proportional to the absolute temperature.
 
You know the R at the working temp T -- you've solved it. You also know R at 37 C. Any ideas?
 
Shooting star said:
You know the R at the working temp T -- you've solved it. You also know R at 37 C. Any ideas?

No sorry i dont. I know this is almost certainly something simple which will make me feel stupid when I see the answer but at the moment I don't have the figgiest. My best guess would be to assume that the reistance and the temperature are related linerly?
 
Why would that be your guess? It's GIVEN in the problem, in the sentence you had mistyped. Refer post #3.
 

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