Can someone please see if I am approaching this question in the right way ?
Q: Consider the filament of a 230 V 100 W lamp made from 500 mm Tungsten at resistivity (7 x 10^-7). What is the radius of the filament wire ?
My answer so far:
Using P=IV, 100=230i so current is 0.43 A. Now find resistance by R= V/I so (230/0.43) = 535 Ohms. Then substitute into the equation R=pL/A.
Is this the right way to do this question ? Is my resistance correct ?
Resistivity Question watch
- Thread Starter
- 08-11-2008 20:08
- 08-11-2008 20:19
Looks it to me. Shove the resistance, resistivity and length into the equation and there you are.
But remember, you need to find radius, not area, so it's area=Pi*r^2
So r=root of (area/pi.)
Or at least, that's what I'd do