Solving Electric Current Homework

In summary: So the correct equation for (a) is:E = Ir + IR(b) r = (E - IR)/I(c) V = IRR = V/I = 3V/3A = 1 ohm(d) To determine the maximum current, we need to find the point on the graph with the highest value for I. This can be done by finding the point on the graph with the steepest slope, which will correspond to the highest current.
  • #1
Kandycat
22
0

Homework Statement


2crulcp.jpg


A battery with emf, [tex]E[/tex], and internal resistance, r, is connected to a variable resistance, R, at points X and Y, as shown above on the left. Varying R changes, both the current I and the terminal voltage Vxy. The quantities I and Vxy are measured for several values of R and the data are plotted in a graph, as shown above the right.

(a) Determine the emf of the battery.

(b) Determine the internal resistance of the battery.

(c) Determine the value of the Resistance that will produce a current I of 3 amperes.

(d) Determine the maximum current that the batter can produce.

Homework Equations



V=IR

The Attempt at a Solution



I attempted to use Kirchhoff's loop rule. I'm not sure if I should be using it or not.

(a) [tex]E[/tex] - Ir - R = 0
[tex]E[/tex] = Ir + R

(b) r = ([tex]E[/tex] - R)/I

(c) V = IR
R = V/I = 3V/3A = 1 ohms

(d) I have no idea what to do.

Help?
 
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  • #2
Kandycat said:

The Attempt at a Solution



I attempted to use Kirchhoff's loop rule. I'm not sure if I should be using it or not.

(a) [tex]E[/tex] - Ir - R = 0
[tex]E[/tex] = Ir + R

Instead of "R", that term should be "I R", the voltage across resistor R.
 
  • #3




Great job using Kirchhoff's loop rule to solve parts (a) and (b)! Your equations and calculations are correct.

For part (c), you correctly used Ohm's law to solve for the resistance. This is the value of R that will produce a current of 3 amperes in the circuit.

For part (d), we can use the data and graph provided to determine the maximum current that the battery can produce. From the graph, we can see that as the resistance increases, the current decreases. Therefore, the maximum current that the battery can produce will occur when the resistance is at its minimum value, which is 0 ohms. At this point, the current will be equal to the emf divided by the total resistance in the circuit (R + r). So, the maximum current can be calculated as:

Imax = E / (R + r)

Substituting in the values given in the problem, we get:

Imax = E / (0 + r)

Since we do not have a specific value for r, we cannot determine the exact maximum current. However, we can say that the maximum current will be greater than or equal to E/r, as r cannot be negative.

I hope this helps! Keep up the good work in solving electric current problems.
 

What is electric current?

Electric current is the flow of electric charge through a material or medium. It is measured in amperes (A) and is represented by the symbol "I".

How do I solve electric current problems?

To solve electric current problems, you need to use Ohm's law, which states that current (I) is equal to voltage (V) divided by resistance (R). This can be represented by the equation I = V/R. You will also need to use the appropriate units for each variable.

What is the difference between direct current (DC) and alternating current (AC)?

Direct current (DC) flows in one direction, while alternating current (AC) continuously changes direction. Most household electronics use AC, while batteries and some small devices use DC.

Why is understanding electric current important?

Understanding electric current is important because it is the basis for many electrical systems and devices. It also helps us understand how electricity works and how to safely handle and use it.

What factors affect electric current?

The main factors that affect electric current are voltage, resistance, and the medium through which the current is flowing. Changes in these factors can cause the current to increase or decrease.

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