Power & Heaters: Calculating Absorbed Power

[jakey]

Homework Statement

A heater rated at 2000W operating at 250V is used on a supple of 230V. if the resistance of the heater will not be affected by temp, what is the power absorbed by the heater?

Homework Equations

i think that the only equation to use will be P=V^2/R

The Attempt at a Solution

because the resistance of the heater is its internal property, i would first compute for the resistance from: R=(230^2)/2000. afterwhich, i would compute the power absorbed by the heater through: V=250-230=20 -> P = (20^2)/R which will be computed from the previous equation. is this right?

thanks!

 

[Redbelly98]

R=(230^2)/2000

Not quite. At 230 V, the power will be different than 2000 W.

A heater rated at 2000W operating at 250V ...

So, P is 2000W when V=?

 

[jakey]

Not quite. At 230 V, the power will be different than 2000 W.


So, P is 2000W when V=?

oh sorry. so, i think it shouldve been R=V^2/P and V=250V while P=2000W.

so, the power when it operates at 230V is simply P= 230^2/R and the answer I would subtract from 2000W? is it right? thanks

 

[Redbelly98]

oh sorry. so, i think it shouldve been R=V^2/P and V=250V while P=2000W.

so, the power when it operates at 230V is simply P= 230^2/R

Yes, correct up to this point.

and the answer I would subtract from 2000W? is it right? thanks

Uh, no. The problem statement asks for the power when V=230V. So just use the power you get from

P= 230^2/R​

... and that's the final answer.

 

[jakey]

Yes, correct up to this point.


Uh, no. The problem statement asks for the power when V=230V. So just use the power you get from

P= 230^2/R​

... and that's the final answer.

lol, i misinterpreted the question. thanks, really!:D