-1
$\begingroup$

The only solution stuck in my head goes through finding the resistance from the slope of the curves and using it somehow in the solution, however, I can't figure out what voltage do I use for X and Y? (The current will obviously be the same for both.)

How does one approach exercises of this type?

Two resistors, X and Y, have I–V characteristics given by the graph.

enter image description here

The resistors X and Y are connected in series to the same cell. Estimate the total current leaving the cell in this circuit.

P. S. The resistors X and Y connected to a cell of emf 1.5 V

enter image description here

$\endgroup$
9
  • 2
    $\begingroup$ What is the voltage of the cell? $\endgroup$
    – Jon Custer
    Apr 28 at 19:01
  • $\begingroup$ I've included it. $\endgroup$
    – Ziezi
    Apr 28 at 19:03
  • 2
    $\begingroup$ OK. Now, the current is the same through each resistor since they are in series. So, how can you figure out the current? $\endgroup$
    – Jon Custer
    Apr 28 at 19:06
  • 2
    $\begingroup$ Forget equations - solve it using the graph. $\endgroup$
    – Jon Custer
    Apr 28 at 19:25
  • 1
    $\begingroup$ should the current be such that the voltage adds up to 1.5V or something like that? $\endgroup$
    – Ziezi
    Apr 28 at 19:31

2 Answers 2

1
$\begingroup$

The slope of the $I\ \text{against}\ V$ curve gives the reciprocal of the so-called 'slope resistance', $\frac{dV}{dI}$. This can be a useful concept, but it's not relevant here.

Here are some hints as to how to proceed...

• What quantity is the same for both resistors?

• A family of straight lines can be imagined to be drawn on the graph grid. Each straight line represents a particular value of this quantity.

• What is the relationship between the voltages across X and Y and the voltage provided by the cell?

• If you knew the cell voltage you'd be able to select which of the lines that you imagined is the right one!

$\endgroup$
0
$\begingroup$

The current is the same thorough both resistors; the total voltage drop across both resistors is 1.5 V (neglecting resistive losses in the battery). With these constraints, using the graphs, you can calculate the current. What do you calculate for the current?

$\endgroup$

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