1
$\begingroup$

Calculate the voltage between terminals a and b.

I am confused about a problem. I've tried to solve this using the second Kirchoff's rule, but my solution is equal to 0. What am doing wrong?
E=5V R1=600Ω R2=400Ω circuit

My calculations was:
U=R*I
I=5V/1000Ω=0,005A
U=-R1*I+E-R2*I
U=-600*0,005+5-400*0,005=-3+5-2=0[V]

What is wrong?

$\endgroup$
2
  • $\begingroup$ I've added the homework-and-exercises tag. In the future, please use this tag for this type of question. Also, please mark up your math using mathjax. $\endgroup$
    – user4552
    Jan 29 '19 at 20:01
  • $\begingroup$ You get zero because the voktages along a closed loop must add to zero. The desired voltage is hidden in your final calculation. $\endgroup$
    – Jasper
    Jan 29 '19 at 20:05
0
$\begingroup$

According to Kirchoff's voltage law, the sum of the potential drops and rises in a circuit is equal to zero.

$E -iR_1-iR_2=0$

$U=E-iR_1$ $=iR_2$

where $U$ is the potential difference across resistor $R_2$.

For an intuitive basis, think that the charge gets an energy $V$ when it passes through the battery, and it dissipates that when it goes through the resistors. By the end of the journey, it's energy is zero. That's what the rule kind of states.

$\endgroup$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.