Voltage and Resistance Exercise, .

[claudiadeluca]

Please help with the following exercise:

Given 2 resistors in series R1=10 ohms, R2= 30 ohms, determine the current flowing through the resistors and the voltage across each resistor, if the potential difference across the wire is V=12V.

This is how I solved it:

The total resistance Req= R1+R2= 40 ohms

R = V / i
i = V/R = 0.3 A

V(R1) = -R1*i = -10*0.3= -3V
V(R2) = -R2*i = -30*0.3= -9V

Is it correct? Can the voltage be negative? Please help.

Thank you.

 

[Mindscrape]

Voltage can be negative because it is a relative measurement.

I don't think you did yours right though. Draw the circuit out, and sum the voltages. They should sum to zero because of energy conservation, or otherwise known as Kirchoff's Voltage Law.