Electronics - RL Circuits - Discussion

3. 

What is the true power of a 24 Vac parallel RL circuit when R = 45 omega.gif and XL = 1100 omega.gif?

[A]. 313.45 W
[B]. 12.8 W
[C]. 44.96 W
[D]. 22.3 W

Answer: Option B

Explanation:

No answer description available for this question.

Ranjit said: (Sep 2, 2011)  
No power is dissipated in L...
So P=(Vpow2)/R

Soundarya said: (Sep 27, 2011)  
There is no dissipation of power at inductor.so
p=v^2/R
=(24*24)/45=12.8 is the answer

C.P. Borkar said: (Nov 25, 2011)  
First calculate

I=V/R =24/45 = O.533

THEN P=VI
P=24*0.533
P=12.8

Hareshwar said: (Jan 20, 2012)  
Good answer.

Sindhu Priya said: (Aug 27, 2012)  
I=V/R=24/45=0.533
P=VI=24*0.533=12.8

Lochana.Vyas said: (Apr 24, 2013)  
As they said only true power so inductance value will not be there and only purely resistive load is used:-.

V^2/R = (24) ^2/45 = 12.8W.

Nasim said: (Sep 1, 2013)  
Please say why there is no power dissipation in the inductor?

Arun said: (Oct 29, 2013)  
Impedance z = 44.9 ohm.

I = V/Z = 0.534 A.

TRUE POWER = V*I*COS(PHI)=12.78 VOLT.

PHI = TAN inv(R/Xl) = 2.34.

Sudhi. said: (Dec 10, 2014)  
If there is no losses in the inductor it is simple. This means no equivalent series or parallel are. Use 2pi x f x L to get the reactance, and then the current by ohms law.

There is no power dissipated. Current is drawn but it recirculates without any heating. The inductor charges and discharges.

Rajan said: (Nov 16, 2016)  
Another way is total I * V.
There is a power dissipated in the resistor and also low lost in Inductor.
So both need to be considered !

In parallel circuit Total current It= IL +Ir but since they are not in the same phase so cannot plus directly.

It^2 = IL^2 + Ir^2.

Ir = V/R =24/45 = 0.533.
IL = V/Xl =24/1100 = 0.0218.

It = sqr(IL^2 +Ir^2) = sqr(0.5333*0.5333 +0.02182*0.02182) = 0.53345.

It = 0.53345 ampere.

Power = VIt = 24 * 0.5334 = 12.80 (more accurate).

Priti said: (Apr 9, 2017)  
Ir=24/45(voltage equal in parallel).
Then,
Real power =Ir^2 * 45 = 12.8.

Pawan said: (Aug 12, 2018)  
Why is inductive reactance not considered here?

Anyone, please explain.

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