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secondary 4 | A Maths
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I’m really confused I can’t solve this question. Would appreciate detailed worked solution. Thank u!
Date Posted: 4 years ago
Views: 233
Actuall the system is a series of 3 resistors in parallel.
but there’s quite a few unknowns and I’m a little confused
Hang on, attempting
Thank you for the solutions!! However I’m a little confused about the second part where u said total voltage of the parallel circuit is 1.5V and not 1.5V + 1.5V, I don’t understand why this is so... Also then does this mean that the other 1.5V is used up in the other resistor connected in series to the ones I’m parallel? Thank u!
Good evening Cheryl! As to why the voltages are the same, you will need to understand the concept of potentials. As long as a path is not blocked by any resistor, the potential values across those paths will be the same, but at any point there is a "cross-over" from one end of the resistor to the other end, the potential "drops".
And yes, due to this same reason, the 1.5 V is consumed at the 1.0 ohm resistor.
Tonight when I am less tired and if I can remember, I will redo the diagram, this time with coloured parts of the circuits (same colour for the same potentials) to explain what I meant.
And yes, due to this same reason, the 1.5 V is consumed at the 1.0 ohm resistor.
Tonight when I am less tired and if I can remember, I will redo the diagram, this time with coloured parts of the circuits (same colour for the same potentials) to explain what I meant.
okay thank you!!
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done
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The circuit which is presented in the question can be redrawn into my version. It does not matter whether they are connected in a triangle manner or not. They key connection between the two ends remain the same, so we simplify the diagram by drawing your familiar rectangular shaped diagrams.
Let me know if you need more explanation, because I know it's quite complicated.
Let me know if you need more explanation, because I know it's quite complicated.
Date Posted:
4 years ago
Good evening Cheryl! You can do a direct transition from my second diagram to my third diagram for simplicity before you look at my workings on the second line. The two diagrams are equivalent diagrams.
The approach that I undertook for my question is this.
1. Attempt to find current flowing through the circuit when the switch is OPEN
2. Attempt to evaluate the EMF of tbe battery, which is the only thing unchanged in the circuit in BOTH scenarios
3. Attempt to find current flowing through the circuit when the switch is CLOSED
4. Find out how much of this current goes to each branch of the PARALLEL component of the circuit
5. Obtain the value of R
1. Attempt to find current flowing through the circuit when the switch is OPEN
2. Attempt to evaluate the EMF of tbe battery, which is the only thing unchanged in the circuit in BOTH scenarios
3. Attempt to find current flowing through the circuit when the switch is CLOSED
4. Find out how much of this current goes to each branch of the PARALLEL component of the circuit
5. Obtain the value of R
thanks!
I also drew the current direction wrongly.
I update this now.
I update this now.
done
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Good evening Cheryl! Here are my updated explanations for this question.
All points along the same colour are at the same potential simply because there is no resistor blocking the way along the same colour paths. All the points along the same colour wires are at the same potential. As such, the potential at Y and Z are the same, and similarly, the potential at C and D are the same. Note, however, that the potential at Y and C are not the same all because of the resistor.
Voltage across the resistor (between C and Y) is defined to be the difference in potential levels across the resistor. So for example, if point Y is at a potential level of 2.5 V (and so do W, X and Z), point C must lie at a potential level of 1.0 V (and so do A, B and D).
The highest potential level starts fresh from the positive end of the terminal (at 3.0 V) before dropping along the 1.0 ohm resistor by 1.5 V to a potential level of 1.0 V along WXYZ and dropping further by 1.5 V across the resistors in parallel to a potential level of 0 V along ABCD. Potentials return to the negative end at a level of 0 V and then regenerates again at the positive end fresh at 3.0 V.
All points along the same colour are at the same potential simply because there is no resistor blocking the way along the same colour paths. All the points along the same colour wires are at the same potential. As such, the potential at Y and Z are the same, and similarly, the potential at C and D are the same. Note, however, that the potential at Y and C are not the same all because of the resistor.
Voltage across the resistor (between C and Y) is defined to be the difference in potential levels across the resistor. So for example, if point Y is at a potential level of 2.5 V (and so do W, X and Z), point C must lie at a potential level of 1.0 V (and so do A, B and D).
The highest potential level starts fresh from the positive end of the terminal (at 3.0 V) before dropping along the 1.0 ohm resistor by 1.5 V to a potential level of 1.0 V along WXYZ and dropping further by 1.5 V across the resistors in parallel to a potential level of 0 V along ABCD. Potentials return to the negative end at a level of 0 V and then regenerates again at the positive end fresh at 3.0 V.
Date Posted:
4 years ago
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