Kirchhoff's Laws

Question

The voltage provided by the battery for the circuit powering two lamps in series is 6 V. If one of the lamps has a voltage of 2 V, what is the voltage across the other?

Answer 1

In terms of conservation of energy, Kirchhoff's voltage law (KVL) is the sum of all the voltages equal to zero.

 

∑V = 0

 

voltage of battery + voltage of one lamp + voltage of 2nd lamp = 0

 

This is similar to what Arturo mentioned to you.

 

 

You should know that the negative and positive signs are determined by the battery terminals.  If the electron enters through the positive terminal of the voltage, then positive sign.  Otherwise, negative sign.

 

Answer 2

By Kirchhoff's first law, the sum of the voltages must be 6V.  If one of them is 2V, the other is (6 - 2)V = 4V.