How do you calculate the total resistance?

In summary, the conversation is discussing a question about finding the total resistance in a circuit. The question is Question 38 and the answer is 92. The conversation involves trying to solve the question and discussing the correct method to do so. The conversation ends with one participant quitting and the other participant suggesting to replace the 30Ω and 15Ω resistors with their equivalent to solve the question.
  • #1
Zoro
18
0

Homework Statement


What is the Total resistance in Question 38.

Homework Equations

The Attempt at a Solution


I tried drawing the circuit again splitting up the series and parallel but i got the wrong answer. The answer is 92. Like i know that the 60 is parallen to 15 and the 15 is parallel to 10. The 15 and 5 are in series and the 20 and 10 are in series and maybe also 5. [/B]
 

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  • #2
"3. The Attempt at a Solution "
 
  • #3
Zoro said:

Homework Statement


What is the Total resistance in Question 38.

Homework Equations

The Attempt at a Solution


I tried drawing the circuit again splitting up the series and parallel but i got 93. The answer is 92. Like i did 40 + 40 + 10+ 1/((1/60)+(1/15) + 1/20 + 1/10 + 1/5)[/B]
You took all the 60 Ω, 15Ω, 20Ω, 10Ω, 5 Ω resistors parallel; they are not.
 
  • #4
ehild said:
You took all the 60 Ω, 15Ω, 20Ω, 10Ω, 5 Ω resistors parallel; they are not.
So what now
 
  • #5
The ammeter can be replaced by a single wire. How are the 10Ω and 20Ω resistors connected?
 
  • #6
ehild said:
The ammeter can be replaced by a single wire. How are the 10Ω and 20Ω resistors connected?
Well, it doesn't say. It's just in series judging by the diagram
 
  • #7
Zoro said:
Well, it doesn't say. It's just in series judging by the diagram
You need to use the diagram.
Yes, they are in series. What is their resultant? How that resultant is connected to the 15 Ω resistor?
 
  • #8
ehild said:
You need to use the diagram.
Yes, they are in series. What is their resultant? How that resultant is connected to the 15 Ω resistor?
Resultant? like 10 + 20 = 30 ?
 
  • #9
Zoro said:
Resultant? like 10 + 20 = 30 ?
Yes. Now you replace the 10Ω and 20Ω resistors with their series equivalent. How is that 30Ω resistor connected to the 15Ω resistor?
 
  • #10
ehild said:
Yes. Now you replace the 10Ω and 20Ω resistors with their series equivalent. How is that 30Ω resistor connected to the 15Ω resistor?
I did this earlier. Is it correct
 

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  • #11
Zoro said:
I did this earlier. Is it correct
The diagram is correct. What is the result?
 
  • #12
ehild said:
The diagram is correct. What is the result?
80 + 1/ (1/60 + (1/20) + (1/30) = 90 =/= 92
 
  • #13
Zoro said:
80 + 1/ (1/60 + (1/20) + (1/30) = 90 =/= 92
Yor calculation is wrong. How are the 30Ω and 15 Ω resistors connected?
 
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  • #14
ehild said:
Yor calculation is worong. How are the 30Ω and 15 Ω resistors connected?
wat
 
  • #15
Zoro said:
wat
?
I quit. Good luck.
 
  • #16
ehild said:
?
I quit. Good luck.
LOl. wtaf man. can you just stop beating around the bush and hit the turkey on the head already?
 
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  • #17
Forum rules don't allow us to just give you the answer. For why see..

http://tinyurl.com/os67nwp

Next step (as ehild said) is to figure out how the 30Ω and 15 Ω resistors are connected? Series? Parallel? Replace these two with their equivalent.
 

FAQ: How do you calculate the total resistance?

1. How do you calculate total resistance when resistors are connected in series?

In a series circuit, the total resistance is equal to the sum of all individual resistances. This can be calculated by simply adding together the values of each resistor. For example, if there are three resistors with values of 10 ohms, 20 ohms, and 30 ohms, the total resistance would be 10 + 20 + 30 = 60 ohms.

2. How do you calculate total resistance when resistors are connected in parallel?

In a parallel circuit, the total resistance is calculated differently than in a series circuit. It is equal to the reciprocal of the sum of the reciprocals of each individual resistance. In other words, 1/RT = 1/R1 + 1/R2 + 1/R3 + ... where RT is the total resistance and R1, R2, R3, etc. are the individual resistances. For example, if there are three resistors with values of 10 ohms, 20 ohms, and 30 ohms, the total resistance would be 1/(1/10 + 1/20 + 1/30) = 6 ohms.

3. How do you calculate total resistance when there are both series and parallel resistors in a circuit?

In this case, you can first calculate the total resistance of the resistors that are connected in series. Then, you can calculate the total resistance of the resistors that are connected in parallel. Finally, you can use Ohm's Law (V=IR) to find the current through each resistor and add them together to find the total current in the circuit. This total current can then be used to calculate the total resistance using Ohm's Law again (R=V/I).

4. How does the total resistance change when resistors are added in series or parallel?

When resistors are added in series, the total resistance increases. This is because the current has to pass through each resistor in succession, resulting in a larger overall resistance. When resistors are added in parallel, the total resistance decreases. This is because the current has multiple paths to flow through, reducing the overall resistance.

5. What happens to the total resistance when resistors are replaced with ones of different values?

If resistors are replaced with ones of different values, the total resistance will change. In a series circuit, if a resistor with a larger value is added, the total resistance will increase. If a resistor with a smaller value is added, the total resistance will decrease. In a parallel circuit, adding resistors with larger values will decrease the total resistance, while adding resistors with smaller values will increase the total resistance.

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