Activity 8-3 D: RESISTORS AND OHMS LAWName:

Date:

Block:

Purpose: We will be using the Phet simulation to construct a circuit using resistors. We will be taking measurements from an ammeter to see how the voltage of the source will affect the current of the circuit. We will then graph these values, calculate the slope to find the resistance, and compare this slope value to the value of the resistor in the circuit.

Instructions:

  1. Log on to your computer
  2. Go to the following website:
  3. In the Search area, type in “Electricity” and click “Go”.
  4. Click on the application that says Circuit Construction Kit (DC only).
  5. Click “Run now.”
  6. Construct the circuit below (you will need to right click on the battery to change it to 1.5V):
  1. Right click on your resistor and change the resistor value to somewhere between 5.0 and 20.0 ohms. Record this value here: ______.
  1. What are the colours of the bands on your resistor (from left to right)? ______, ______, ______, ______
  2. Using the colours listed above, put the number associated with the colours in the same order below (use the table on the last page of the handout).

______X 10 ____ +/- ______%

Is this number the same as the one you entered when you right-clicked your resistor?

  1. Enter the voltage value (1.5V) and ammeter value (whatever your ammeter is reading now) in the table below (Trial 1). Choose 5 other voltage values between 1.5V and 20V and write these down in the voltage column (for example, you may choose 3.0V, 6.0V, 12.0V, 13.0V and 19.0V).
  1. Right click on your battery to change the voltage to the values you have chosen and record each reading shown on the ammeter.

Data Table: ______

Trial / Voltage
(V) / Current
(A) / Calculated Resistance
(Ω)
1
2
3
4
5
6
  1. Using Ohm’s Law, calculate the measured resistance for each data set and record it in your table (show work below).
  1. Graph the current (x-axis) vs. the voltage (y-axis) on the attached graph paper. (refer to your Graphing Checklist!!) Make sure to include a line of best fit.

Graph: ______

Discussion Questions:

  1. On your graph, calculate the slope of the line. Show ALL of your work below.
  1. What does the slope of the line represent?
  1. Did your resistance value for the slope fall within the % accuracy for your resistor? (you will need to refer to Step 9) Show your work to explain.
  1. When drawing your graph, you plotted the voltage (V) on the Y-axis and current (I) on the X-axis. In terms of calculating resistance from your graph, does it matter which values are on each axis? Explain.

______

  1. What happens to the electrical energy when electrons flow through aresistor?Isi energy actually lost?

______

6. Why are resistors used in circuits?

______