Help on an exam question

[westos-electric]

Please help me understand this question:

A capacitor of 95 microfarad is connected in parallel with a 20 ohm pure resistor. the group is connected to a 230v 50Hz. calculate the power disipated in the circuit.

Please help and show workings

Thanks
Wayne

 

[pushrod]

Please help me understand this question:

A capacitor of 95 microfarad is connected in parallel with a 20 ohm pure resistor. the group is connected to a 230v 50Hz. calculate the power disipated in the circuit.

Please help and show workings

Thanks
Wayne

I think this is one of those dodgy ones where because it is in parallel you ignore the capacitance and just work out power dissipated from
P = I xV

calculate I or just use P= V²/R

do you have a choice of answers

 

[chris_b_52]

Yes he's spot on. Capacitors and inductors are classed as 'wattless components' and don't dissipate ac power.

You would use the ohms law formula above to calculate the power dissipated by the resistor.

 

[westos-electric]

Hi

I'm not asking for homework to be answered here i'm asking for help to understand what i'm doing, this said are you able to help??

The answer on the sample paper is 2.64kW if i do 230/20 the answer I get is 2645 i take it as it's kW I divide 2645 by 1000?

Hope you are ok to help

 

[pushrod]

Hi

I'm not asking for homework to be answered here i'm asking for help to understand what i'm doing, this said are you able to help??

The answer on the sample paper is 2.64kW if i do 230/20 the answer I get is 2645 i take it as it's kW I divide 2645 by 1000?

Hope you are ok to help

Only too pleased to help - its just if i give you the answer straight away i am denying you the chance to puzzle over it yourself and get the right answer , which you did above . The more input from you the more you learn.

(230 x 230) ÷ 20 = 2645 W or as you said 2.645 kW

 

[westos-electric]

Awesome cheers, i'm looking these up but it helps to have someone point you in the right direction!

I may have a few more but not just yet

Thanks again
Wayne