Question

I know it is not a maths question, but I couldn't find a physics study group, so: An electric radiator which is an ordinary constant resistor emits a heating power of
750 W at a mains supply voltage of 230 V. What is the total heating power in each respective
instance when two such radiators are connected a) in parallel, and b) in series to the 230 V
supply voltage?

i think i need to find the resistance of radiator first am I right?

Answer 1

i found the resistance of each radiator to be 70.5333 ohms, but what do I do now?

Answer 2

You're right about the first part.

Answer 3

You next have to set up your circuit where each radiator is represented as a resistor.

Answer 4

i did, i have drawings ow both cases, series and parallel

Answer 5

Whenever I see resistance, voltage and power, I think of the following:\[V=IR\]and\[P=IV\]Eliminate current as such\[I=V/R \rightarrow P =(V/R)V=\frac{V^2}{R}\]

Answer 6

The resistance here will be the effective resistance of the circuit. For the parallel case, \[\frac{1}{R}+\frac{1}{R}=\frac{1}{R_{eff}} \rightarrow R_{eff}=\frac{R}{2}\]and so to find the power for parallel:\[P=\frac{V^2}{R_{eff}}=\frac{V^2}{R/2}=\frac{2V^2}{R}\approx \frac{2 \times 230^2}{70.53}=1500W\]

Answer 7

For the series case, \[R+R=R_{eff} \rightarrow P=\frac{V^2}{R_{eff}}\approx \frac{230^2}{2 \times 70.53} \approx 375W\]

Answer 8

great, I understand it now! THANX, you are a leal lifesaver, i wish i could become your fan again

Answer 9

wait, let me create another account and fan you once more...

Answer 10

[thumbs up] :)

Answer 11

here I am

Answer 12

lol awesome

Answer 13

:( do not see the fan button :( something is wrong... w8 let me try some proxy manipulation...

Answer 14

I've heard people say they have to refresh the page or something...in any case, at least you have a cool login.

Answer 15

Ah...excellent!

Answer 16

yay, my little hack worked, appearently openstudy wont allow liking on a same user from one IP address, so i used some proxy server to do it

Answer 17

smart!

Answer 18

let me try again..

Answer 19

You know, I think there is something for physics on this openstudy site. I haven't checked properly, but I saw something about physics on the homepage. You have to load more or something...

Answer 20

click on more groups, and there's something callled physics classical openstudy something.

Answer 21

yes...that's it

Answer 22

^^