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erocored
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Why we say that the resistance of the series curcuit is equal to the sum of the resistances of the resistors?
Why is it possible?kuruman said:It's not equal, it's equivalent. This means if you replace the two resistors with a single resistor, it will draw the same current.
Ohm's law makes it possible. Say you connect a ##5 \mathrm{\Omega}## resistor to a 10 V battery. Ohm's law, ##V=IR## says that the current is ##I=V/R=2~ \mathrm{A}##. Now connect two resistors, ##R_1=2 \mathrm{\Omega}## and ##R_2=3 \mathrm{\Omega}##, in series to the same battery. "In series" means the current through each resistor is the same. Call that current ##I'##. The voltage across the series combination is the voltage across the battery, 10 V. It is also the sum of the voltage drops across each resistor. Then $$I'R_1+I'R_2=I'(R_1+R_2)=I' (5\mathrm{\Omega})=10~\mathrm{V}.$$You can see that the combination draws the same current, i.e. ##I'=I=2~ \mathrm{A}.##erocored said:Why is it possible?
I think the current is the electrons that move because of potential difference. When electrons passing through a resistor they lose some of their kinetic energy. I guess that we can calculate common resistance by the sum of the resistance R1 and R2 because total less of energy wil be equal to loss of energy if current goes through the resistor of resistance R1+R2. But I can't understand why the electrons don't get energy going through BC?anorlunda said:@erocored, In this thread and your other thread, you seem to have a misconception about what electric current is. Your questions have been answered, but that doesn't seem to help. Tell us in your own words what you think current is, and how you think it should behave.
erocored said:When electrons passing through a resistor they lose some of their kinetic energy.
Because there are no power sources between B and C.erocored said:But I can't understand why the electrons don't get energy going through BC?
Noddy answer coming up:erocored said:. When electrons passing through a resistor they lose some of their kinetic energy.
That is it in a nutshellvanhees71 said:Well, the kinetic energy of the conduction electrons is negligible in energy transport for usual household currents. What transports the energy along the circuit is the electromagnetic field.