I am looking at the problem in page 5 of this document. It is an example of KVL (Kirchoffs voltage law).
The circuit is as shown below -
.
I have 2 questions -
1) Why is the voltage -5V ? Is it because the polarities reversed ? 2) The sign convention in the 8 Ohms resistor is wrong as I assumed the current loop as shown below and the sign convention as stated in the diagram. The voltage across 8 Ohms is -12V. Is the minus sign because of wrong convention ?