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What is the relationship between current and resistance?
- Thread starter Gear300
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In summary, the conversation discusses the concept of current flow through resistors in a circuit. The individuals are discussing the behavior of the circuit when S1 and S2 are closed at different times. It is noted that when S1 is closed, the voltage across C is equal to E, creating an open circuit. When S2 is then closed, there is no current through R1 because the potential difference across it is 0. However, as C discharges through R2, the potential difference across R1 becomes greater than 0, causing current to flow through R1 and constantly charging up C. The net effect is that C remains a spectator in this process. The conversation also mentions a graph that shows the behavior of the circuit, with
- #2
mjsd
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After C has been charge up (ie. S1 closed for a long time). The Voltage across C is same as E, effectively you have an open circuit at C. So initially, when S2 is closed, there cannot be any current through R1 because potential difference across it is E-V_C = 0, but as C discharges through R2, V_C drops and now E-V_C >0 and so E will charge up C again via R1 (so current through R1 becomes non-zero). And so as C discharges through R2, E through R1 constantly charges C up again. I believe the net effect would be that C is just a spectator in this process.
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Gear300
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Wouldn't the current running through R1 also run through R2 because there is an open circuit at C? And the process you described seems to run like you said in that last sentence...that C would remain a spectator. In that case, when S2 is closed, can C be ignored?
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Gear300
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Better yet...here is the link to the graph: http://www.collegeboard.com/prod_downloads/ap/students/physics/ap06_sg_physics_c_em.pdf
Its on the bottom of page 8
Its on the bottom of page 8
1. What is the relationship between current and resistance?
The relationship between current and resistance is described by Ohm's Law, which states that the current (I) flowing through a conductor is directly proportional to the voltage (V) and inversely proportional to the resistance (R). This can be expressed as the equation I = V/R.
2. What is the unit of measurement for resistance?
The unit of measurement for resistance is the ohm (Ω). This is represented by the Greek letter omega (Ω) and is named after the German physicist Georg Ohm, who first described the relationship between voltage, current, and resistance.
3. How does temperature affect resistance?
In general, as the temperature of a material increases, its resistance also increases. This is because temperature causes the atoms in a material to vibrate more, which creates more collisions for the electrons to navigate through. However, some materials, such as semiconductors, have a decrease in resistance with an increase in temperature.
4. What factors can impact the resistance of a material?
The resistance of a material is affected by its length, cross-sectional area, and type of material. Longer materials will have a higher resistance, while materials with a larger cross-sectional area will have a lower resistance. The type of material also plays a role, as different materials have different atomic structures and different abilities to conduct electricity.
5. How is resistance measured?
Resistance is typically measured using a device called a multimeter, which can measure the voltage and current of a circuit and calculate the resistance using Ohm's Law. Resistance can also be measured by using a Wheatstone bridge, which compares the unknown resistance to a known resistance and calculates the unknown value.
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