Physics Lab Experiment Ohms Law Finding Resistance Lab Report

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Physics Lab Experiment Ohms Law Finding Resistance Lab Report

Lab 2

Name__________________________________________ Due date: October 5 

  1. I. The objectives of this lab are(1) to determine the resistance of a cylindrical resistor experimentally (2) to compare the experimental ( E ) value of resistance with the actual (A) value of resistance.
  2. Apparatus(Equipment): Voltage source, ammeter that measures current , voltmeter that measures voltage.

III. Procedure:  The currents (I) flowing through a resistor were measured by applying different amounts of voltages (V) to a resistor.

  1. IV. Raw Data: The voltages applied, and the corresponding currents  are indicated in the raw data table below

 

 Voltage applied, V (v) Current, I (milliampere)    Resistance, R ( Ohms)
6 250  
12 333  
18 600  
24 923  
30 1200  

 

  1. V. DATA ANALYSIS: (1)Using Ohm’s Law and showing your steps , calculate the value of resistance R or each row in the above table. You need to convert milliampere to  Ampere while using Ohm’s law .  Note that 1 ampere = 1000 milliampere. You will get a total of five  values of R. (2) Determine the average of the five values of R. The average value of R will be the Experimental Value of the resistance. Usually it is denoted by the letter E (E is used to indicate that it is an experimental value). The Actual value of resistance is indicated by   the letter  A .

The actual value of the resistance of the resistor determined by the manufacturer is  A = 30 Ohms   

 Percent error =  X 100 %  =  

(3) Calculate the percent error by  using the value you obtained for the experimental resistance (E ) and the actual resistance A = 30  Ohms   

 

 

 

  1. VI. QUESTIONS:
  2. If the length L and area A of the resistor were measured, is it possible to identify the type of material within the resistor? Explain.

 

  1. The variables in Ohm’s Law are V, R and I. The variables in Newton’s second Law are Fnet, M and a. Explain that Ohm’s Law is similar to Newton’s second law by indicating the similarity of the variables in the two laws. For each variable in Ohm’s law , find the corresponding variable in Newton’s second law and explain why they are similar.

 

 

  1. Using the first row data, calculate the number of electrons that flow in the resistor in one second. Explain.

 

  1. Suppose the experiment was repeated by applying the same voltages using another (new) cylindrical resistor made from the same material used for the resistor in the experiment. If the new resistor has the same length (L) but twice the area as the one used in the experiment, will the currents stay the same, double or halve? Why?

 

 

 

VII. Sources of Error: What are the possible sources of error for this experiment?

 

 

VIII. Conclusions: Write down your conclusions. In your conclusions describe if you achieved your objectives and what you have learnt from the experiment.