Electrical Engineering - Parallel Circuits - Discussion

Discussion Forum : Parallel Circuits - General Questions (Q.No. 2)
The total resistance of a parallel circuit is 50 . If the total current is 120 mA, the current through the 270 resistor that makes up part of the parallel circuit is approximately
22 mA
120 mA
220 mA
50 mA
Answer: Option
No answer description is available. Let's discuss.
16 comments Page 1 of 2.

Raguram said:   2 years ago
Whatever may be a count of the resistance in parallel.
That's not important here ...

here, they were given total resistance and total voltage and all the resistance is connected in parallel.
Let's make it simple..voltage across each resistance is the same (because of the parallel circuit)

Total voltage = voltage drop in anyone of the resistance part.

Total current * Total resistance = Individual current* particular resistance value,
50 *120 = x *270.
X = (50 *120)/270.
X ~ 22mA.

Azeem said:   7 years ago
Voltage division For Series Circuits.
Vr = (R/Req) * V.

Current Division for parallel circuit
Ir = (Req/R) * I.

Where Req is the equivalent resistance (either series or parallel.
R is the resistance for which you want to determine the voltage or current.
Ir and Vr are the current and voltage respectively of the resistor in question.
I and V are the current and voltage respectively to be divided.

ABD said:   9 years ago
I think we can do by ohm's also. In first case we know resistance value and current by this we can find voltage value. In second case we we know resistance value and we already find voltage in first case by using these we can find current.

Ex : Case 1:

V = IR.
V = 50*120 ma.
V = 6 volt.

Case 2:

I = v/r.
I = 6/270.
I = 22 ma.

Let me know this method is correct or not.

MOHIT RAJHANS said:   1 decade ago
R1 and R2 are in parallel,

So (R1) * (R2) / (R1+R2) =50.

R1 = 270 ohm, R2 is unknown.

We get R2 = 61. 3 ohms.

Now using current division rule we get,

I2 = (Total current) * (R2/R1+R2).

= 120* (61/331).

= 22 mA.

That is the required answer, hope you people understand.

Ramesh said:   1 decade ago
Total Resistance=50
R1 and R2 are in parallel.
R1=270 ohms (given)
where m=(Total Current/Current through 270 ohms)
Using above formula find out the current through 270 ohms...

Anu said:   2 weeks ago
As the resistances are in parallel so,
Req = R1 * R2/(R1+R2).
So from here, 50 = 270 * R2/(270+R2).
Now, using the current division rule for I, we get;
I2 = I * (R2/R2+R1).
I2 = 22ma.

Sarkars said:   1 decade ago
Concept of raja and ramesh wrong, Sehegal is correct.
Try this way:
Total voltage = 50ohm * 120mA = 6 V
Current through 270 ohm resistor = 6 V/270 ohm = 22 mA

Mrakovic said:   1 decade ago
Ri = 50ohm.

Ii = 120 mA = 0.120A.

R1 = 270 ohm.

U = Ii*Ri = 0.120*50 = 6V.

I1 = U/R1 = 6/270 = 0.022A = 22 mA.

Sindhu said:   9 years ago

This method can be used as you have the total resistance as 50 ohm and total current as 120 mA given.

Raja said:   1 decade ago
According to current div rule.

Current= (total current*total resistance) /particular resistance.

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