- #1
Nuclearhermit
- 2
- 0
[SOLVED] Working Resistance, Vo or VRMS
Hey everyone, I'm new here and just wondering if you can give me a helping hand. In my Physics homework, the following question is stated:
"A heating element for an electric fire consists of a single strand if nichrome wire wound around an insulator. The heater is required to produce 1.2kW when connected to the 230V-RMS ac mains.
(i) Calculate the working resistance of the nichrome wire.
Okay, so it's not that i don't understand how to do the question, it's just that i don't know what it's asking for. Normally it would be okay, but because the 'RMS' was thrown in, it's put me off a bit.
Equations used:
V0 = V-RMS × √2 ------Part 1
P=IV, therefore I=P/V ------Part 2
V=IR, therefore R=V/I ------Part 3
Part 1 ---- V0 = 230v × √2 = 325.269v...
Part 2 ---- I = 1200w/325.269v... = 3.689A...
Part 3 ----325.269v.../3.689A..., therefore R = 88.2 ohms
Simply, what voltage do i use? Do i convert the V-RMS into V0, or leave it alone. I've tried both ways, the latter (not seen here), gives a resistance of 44.06 ohms.
All help is greatly appreciated. Thanks.
Homework Statement
Hey everyone, I'm new here and just wondering if you can give me a helping hand. In my Physics homework, the following question is stated:
"A heating element for an electric fire consists of a single strand if nichrome wire wound around an insulator. The heater is required to produce 1.2kW when connected to the 230V-RMS ac mains.
(i) Calculate the working resistance of the nichrome wire.
Okay, so it's not that i don't understand how to do the question, it's just that i don't know what it's asking for. Normally it would be okay, but because the 'RMS' was thrown in, it's put me off a bit.
Homework Equations
Equations used:
V0 = V-RMS × √2 ------Part 1
P=IV, therefore I=P/V ------Part 2
V=IR, therefore R=V/I ------Part 3
The Attempt at a Solution
Part 1 ---- V0 = 230v × √2 = 325.269v...
Part 2 ---- I = 1200w/325.269v... = 3.689A...
Part 3 ----325.269v.../3.689A..., therefore R = 88.2 ohms
Simply, what voltage do i use? Do i convert the V-RMS into V0, or leave it alone. I've tried both ways, the latter (not seen here), gives a resistance of 44.06 ohms.
All help is greatly appreciated. Thanks.