Power dissipated help!

[kiwiNCFC]

Hi, i am doing some revision for my 301 exam on Friday and I am a little bit stuck on a question.

A single phase circuit dissipates 2.5kw of power and operates a pf of 0.95.

The current flowing is...

11.4A / 10.32A / 10.8A / 10.4A

what I did was this: 2500w/230v (says single phase) I got 10.87A as my answer. Is this the correct way to go about it?

Thanks In advance

 

[Doc Hudson]

Have you not got to bring your pf into it?

Doc H.

 

[Mikeymike]

The Formula is

P

V x P.F

So in this case

its 2500/230 x 0.85 = 11.4A

Hope this helps m8

 

[Doc Hudson]

You need a correction there MikeyMike the questions states pf=0.95 not 0.85.

Doc H.

 

[kiwiNCFC]

Cheers mate, knew i was missing something! Thanks!

 

[kiwiNCFC]

I just did the above calculation and it's wrong. 2500 / 230 is 10.86 x by 0.95 is 10.32? Is this right?

 

[Manator]

That looks right to me

 

[kiwiNCFC]

Hmm weird. I downloaded the questions from this site and the answer booklet gives a different answer. I have noticed this for a few other questions too. Major confusing me !

 

[Manator]

I think I remember Admin mentioning this was a problem with some papers, the wrong answers have been given in some revision papers and can be confusing. The questions should always be worked out, with little regard for the answer. Test papers are very useful to get the layout and direction an exam takes, the questions in revision papers let you see how the exam will look, and the type of questions asked. So when you come to do the real thing you are not going into the exam with no idea of how it works or looks.

 

[kiwiNCFC]

Oh ok thanks for clearing that up. I do go through every question working it out and this proves that i have done that (by querying the answer) I just dont want to revise a way of doing something that turns out wrong. Thanks for all your help!