Electrical Engineering - Series Circuits - Discussion

Discussion :: Series Circuits - General Questions (Q.No.2)

2. 

A string of five series resistors is connected across a 6 V battery. Zero voltage is measured across all resistors except R3. The voltage across R3 is

[A]. 0 V
[B]. 1.2 V
[C]. 6 V
[D]. 0.6 V

Answer: Option C

Explanation:

No answer description available for this question.

Venkata Ramana said: (Jan 7, 2011)  
Since all resisters are connected in series, such that the current flowing through R3 resister is zero (open circuit) , so therefore vr3=6v.

Ramesh said: (Feb 16, 2011)  
IF CURRENT FLOWS THROUGH R3 IS ZERO, THERE MAY NOT BE ANY VOLTAGE DROP i.e v=ixr3 => 0xr3=0.when r1, r2, r4,r5=0,and r3=6ohms , current=1amp, then v3=ixr3=> 1x6= 6ohms.

Seyran said: (Aug 30, 2011)  
In series connected resistors, the flowing current supposed to be equal. If you are measuring across any of the resistors, and the meter reads 0v, it means answer A is right. If you are measuring with the respect to common terminal, 6v reading means that R2 resistor is broken. Explanation is not correct.

Santhosh said: (Sep 1, 2011)  
6volts given to resistor(r1(0)+r2(0)+r3+r4(0)+r5(0))= we obtain the same six volts at the end.

Gurmangat said: (Sep 18, 2011)  
Yes the net voltage is on the R3.

Mani Rathinam said: (Nov 23, 2011)  
I agree with seyran.

Latha said: (Feb 25, 2012)  
In series connected resistors the current flowing through it ll b same but de voltage gets divided. As the question says voltage across the resistors are zero except at r3 which clearly means the entire applied voltage s across r3.

Arul said: (Mar 27, 2012)  
The resistor r3 is connected at first in series. So, the resistance value of the resistor r3 is high to drop that entire 6volt which may be connected to ground. So there is zero voltage appear across next coming series resistor.

Aman said: (Mar 27, 2012)  
In series connection current is always same so value of current across r3 is also zero hence no voltage.

M Ramesh said: (Mar 29, 2012)  
If all resistors are connected in series, the current flow through the all resistors is always same. So value of current across R3 is also zero.

Jagmel Singh said: (Jul 5, 2012)  
@Aman.

You should think that we are talking about zero voltage but not for zero cureent. It means all the resistors except R3 contains zero resistance. So all voltage drop is across register R3 which is the total voltage drop due to current flowing through it opposed by its resistance.

Vivek Singh said: (Oct 24, 2012)  
It means other than R3 all resistance are zero, because of it in series connection current is same,

If I=0 then no meaning of R3.

But according to kirchoff's circuit is false.

So.

If R1, R2, R4, R5=0 then R3=6 if I=1amp.

Viren Waghela said: (Oct 24, 2012)  
In series circuit, value of current remain same. So according to question if value of voltage measure zero across all resistor, means the value of current is zero and it same for all resistor. So answer zero.

Rutesh said: (Jun 12, 2013)  
Simple,

v1+v2+v3+v4+v5 = V,

ir1 + ir2 + v3 +ir4 +ir5 = 6,(V=6),

As per @Satosh formula,

We get v3 = V = 6v.

Sankar said: (Jun 18, 2013)  
Resistor connected in series. Circuit current is 0.5A BUT R1245 VOLT IS 0V. So according to ohm's law V = I*R = 6V.

Mansoor said: (Jun 30, 2013)  
Resistors connected in series, So circuit current is same, Voltage across R1 R2 R4 R5 is zero. V = IR so the current remain zero, Voltage across R3 = IR3 i.e =0*R3 Final answer V3=0 option "A"

Jigar said: (Jul 7, 2013)  
Voltage is wast in resistor. So the measuring value is Zero.

Suman said: (Jul 10, 2013)  
If in the string all resistors are connected in series, than if voltage across R1, R2 is zero then why there can be a voltage on R3. If there is no voltage then there must not be any current flowing.

Please answer me if you have an appropriate one.

Ravi said: (Jul 19, 2013)  
If current through each resistor except R3 is zero. It means that they are open circuit. They have no mean in the circuit. So when current through R1 is zero it will not flow to next resistor. Hence all the resistors will have zero current.

Surya said: (Aug 5, 2013)  
Resistor connected in series. Circuit current is 0.5A BUT R1245 VOLTAGE IS 0V. So according to ohm's law V = I*R = 6V.

Lakmal said: (Aug 8, 2013)  
Like R1245 resistors are 0 ohms. Like a wire. Like 6v battery dirrect connect to R3 resistor. So answer is 6v.

Judhistir said: (Aug 19, 2013)  
Here voltage drop across r1 r2 r4 and r5 is zero. That means r1+r2+r4+r5=0. So voltage across r3 resistor=6v.

Sher Ali said: (Oct 28, 2013)  
I think the Current is same in series circuit. So if all the resistors are 0 ohm then the R3 will be 0 Ohm.

Ahmed said: (Nov 12, 2013)  
Correct answer is A for series case.

It would be correct if the connection is parallel.

Ashok Kumar said: (Feb 11, 2014)  
If they are connected in series then the voltage across R3 is zero. If connected in parallel or series parallelly subdivided then we may conclude about the voltage across R3 is non zero value i.e. 6v.

Priti Singh said: (Feb 11, 2014)  
Voltage is zero means register is shorted i.e. zero valued resistor is present there and therefore the entire value of circuit voltage appears across the resistor having some value. So the right answer will be 6v.

R Rakesh said: (Jun 25, 2014)  
Ohm's law is V = IR, it says that the voltage is directly proportional to the current. Also, the resistance through the all resistors is zero except third resistor which means that, the voltage will not drop in first two resistors. So, definitely 6V from the power source will be go through the third resistor. According to the ohm's law the voltage drop will be occur in third resistor which will not follow in the fourth and fifth resistors, because they given the resistance of next two resistors as zero.

In series circuit, the current through the each resistor will be same, but not voltage which will vary depends upon the resistance. If resistance is high, voltage drop will be high. We can say the resistance in terms of load. So, the voltage across the third resistor is 6V.

S.Sasikumarb.E., said: (Jul 24, 2014)  
Except R3 Resistance, all other resistance are zero so no current flow, so r3 also no current flow and no voltage R3=0.

Akash Ray said: (Dec 11, 2014)  
@Jagmel I agree with you.

AS it is given in resistors 12456 zero voltage. So either the resistance or the current in those resistors may be zero. So answer is 6V.

Sunil said: (Feb 10, 2015)  
A starting all 5 resisters are connected 6 volts, in series connection there are all ways same voltage in all resister. Starting are IS 6V r3 resister is always 6v.

Dheeraj said: (Mar 1, 2015)  
All right series same R3 is same.

Douglas said: (Apr 7, 2015)  
Current flowing through resistors is same and let it be I. Voltage drops across resistors rated zero will be i*r which will be equal to zero. The voltage across resistor 3 will be 6 volts.

Srikanth said: (Jun 1, 2015)  
The value of are is zero no voltage drop then same we flow in circuit.

Kondiba Gaike said: (Sep 20, 2015)  
I known given voltage are same in all resistors i.e. 6v.

Kshirod said: (Jan 25, 2016)  
If the resistors are open then how can we measure voltage across R3?

Jagadesh said: (Feb 22, 2016)  
If the voltage across any resistor is zero that means resistor is shorted and the whole voltage appears across the resistor active in the circuit.

As in the question it is give that R3 is active so the whole voltage appears across it. The voltage give in question is 6v.

Therefore answer: 6V.

Gopalan said: (May 21, 2016)  
Question not having any relevance.

Correct answer for this question is zero.

In a series circuit the voltage drop zero across all resistance except R3 it means this is an open circuit.

Also, it can persume Battery dead. Other circuit shorted should not be a correct argument.
For justifying the given answer you can find out the way.That is all.

Series circuit voltage zero means no current so open circuit or batter dead.

Answer is zero.

Gayathri Ramesh said: (Jul 16, 2016)  
In open circuit there will b zero current so voltage drop is equal to the actual voltage. Since are 1, 2, 4, 5 are zero resistance the net voltage at R3 is 6. Which also means the current in series is same.

Sirkudos said: (Aug 19, 2016)  
The answer 6v is correct because resistance connected in series have different voltage with the same current. In reference to the question, the rest of the voltage are the same but R3 is different. Note only 6V that is the supply voltage.

Sandeep Khandagade said: (Sep 1, 2016)  
According to Question resistors are in series.

And voltage drop in R1, R2, R4 & R5 are zero. Then,

1) Current will also zero in all resistors (V = IR). Because resistor having some resistance according to question.

2) Current in the series is Same so mean Current In R3 will also zero.

3) When current will zero so Vtg will be also Zero (V = IR).

Prakash Pritam said: (Oct 4, 2016)  
From the law,
Input voltage = output voltage,
We have,
Vr1 + Vr2 + Vr3 + Vr4 + Vr5 = Vout = 6. All values are zero except Vr3.
=> 0 + 0 + Vr3 + 0 + 0 = 6,
Hence, Vr3 = 6.

Kola Ashok Kumar said: (Dec 15, 2016)  
The answer is 6v.

> voltage is zero when current is zero or resistance is zero.
Current cannot be zero.
So resistance is zero, may be a short circuit across the resistors.

Raymond said: (Jan 5, 2017)  
It is 6v.

Question states we have voltage to the circuit and Its equal to 6v. (No dead batteries ect. Sorry)

ALL EXCEPT r3 have zero voltage drop-- the question is stating r3 has a nonzero voltage drop. If all the other resistors have zero drops they have zero resistance-- like ideal wire.

So we only have a single resistor in the circuit r3.

If these resistors were in parallel you wouldn't have a circuit for long because you'd have 4 shorts. The question states a series circuit.

So, the voltage drop across a single resistor in a 6v circuit. Then the answer is 6v. No math required.

Abdul said: (May 9, 2017)  
V = IR.
R = V/I,
V = I*V/I.
V = V=6V.

It is the correct answer.

Swati said: (Jun 28, 2017)  
Yes, you are correct @Abdul.

Gijo said: (Jul 7, 2017)  
R3 is an open circuit, so all other resistor voltage is 0, r3 will show 6 voltage.

Shubham Patil said: (Aug 5, 2017)  
If all resistors (except R3 are) considered having zero ohm resistance, then this condition satisfies.

Ajithkumar said: (Sep 14, 2017)  
R3 is load.

Ambika Prasad said: (Dec 30, 2017)  
We know in series,

V=V1+V2+V3+V4+V5
=>6=0+0+V3+0+0
=>V3=6v.

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