Experiment 1 SFE1023 - ohmic lab report PDF

Preview

Summary

ohmic lab report...

Description

EXPERIMENT 1 SFE 1023 ELECTRICITY AND MAGNETISM SEM 1 SESSION 2020/2021

NAME

THUSHIDRASRI A/P ARMUGAM

MATRIC NO

E20191024039

GROUP

A

LECTURER

Dr. Nurul Syafiqah Yap Abdullah

TITLE

PHET SIMULATION OF OHM’S LAW

1.0 OBJECTIVES 1.1 To investigate all the variables involved in a mathematical relationship of Ohm’s Law. 1.2 To state the effect of each variables to the total current flow. 2.0 INTRODUCTION The measurements of voltage, current, and resistance that you will make will be made using direct current (D.C.). D.C. refers to direct current which flows in only one direction down a wire. Usually it is a steady current, meaning that its magnitude is constant in time. “D.C.” can also be used to refer to voltage. Of course, unlike current, voltage does not “flow”. Instead, “D.C. voltage” (or “D.C. potential”) means a constant voltage which has only one polarity. One of the major concepts that will be used in this experiment is Ohm’s law, which we discussed in lecture. This law states the relation among the three quantities voltage, current, and resistance: V = IR where I is the current measured in units of amperes, (I), V is the voltage in units of volts, (V) and R is the resistance in units of Ohms, (Ω). At constant temperature , the potential difference, V across a conductor is directly proportional to the current, I that flows through it. The constant of proportionality is known as resistance of the conductor denoted by R. An easy way to think of this law is to imagine that a "current" flows through a wire just like water flowing through a pipe; the narrower the pipe, the greater the resistance. Remember that current flows from positive to negative, representing the flow of positive charge in the wire. (Remember also that it is really the negatively charged electrons that actually do the moving!) In reality, any circuit element (like a light bulb) can act as a resistor. For experiments and for building circuits, small resistors of known resistance can be added to the circuit. 3.0 APPARATUS For the simulation devise, please visit to the PhET website: https://phet.colorado.edu/en/simulation/ohms-law

4.0 PROCEDURE PART A – Effect of voltage changes towards the flow of current with fix resistance

1. The interface of Ohm’s Law simulation circuit is shown as in FIGURE 1.1. 2. From the PhET interface, the voltage of the battery has set to its minimum value by dragging the knob using the mouse. The same has been done to the value of resistance. The value of current flow in the circuit was observed and recorded. 3. Slowly increased the voltage of the battery from its minimum value to maximum with a chosen fix value of resistance. The value of adjusted voltages and changes of the value of current was recorded in Table 1.1.

FIGURE 1.1: Interface of Ohm’s Law Simulation. TABLE 1.1: Changes of current due to different voltage. Value of fix resistance, R: 500Ω Voltage, V ( ± 0.05V) (0.1 ± 0.05 )V (1.5 ± 0.05)V (3.0 ± 0.05)V (4.5 ± 0.05)V (6.0 ± 0.05)V (7.5 ± 0.05)V (9.0 ± 0.05)V

Current, I ( A ±5 x 10-5A) (0.0002 ± 5 x 10-5)A (0.0030 ± 5 x 10-5)A (0.0060 ± 5 x 10-5)A (0.0090 ± 5 x 10-5)A (0.0120 ± 5 x 10-5)A (0.0150 ± 5 x 10-5)A (0.0180 ± 5 x 10-5)A

PART B – Effect of resistance towards the flow of current with fix resistance 1. A value of voltage has chosen and fixed, then, slowly increased the value of total resistance from its minimum value to maximum. 2. The changes of current flow was observed. The value of adjusted resistance and changes of the value of current was recorded in Table 1.2. TABLE 1.2: Changes of current due to different resistance. Value of fix voltage, V: 4.5V Resistance, R (±..Ω) (10 ± 0.05) Ω (196 ± 0.05) Ω (343 ± 0.05) Ω (500 ± 0.05) Ω (642 ± 0.05) Ω (822 ± 0.05) Ω (1000 ± 0.05) Ω

Current, I ( A ± 5x10-5A) (0.4500 ± 5 x 10-5)A (0.0230 ± 5 x 10-5)A (0.0131 ± 5 x 10-5)A (0.0090 ± 5 x 10-5)A (0.0070 ± 5 x 10-5)A (0.0055 ± 5 x 10-5)A (0.0045 ± 5 x 10-5)A

5.0 RESULTS AND ANALYSIS PART A – Effect of voltage changes towards the flow of current with fixed resistance Based on your collected data in Table 1.1, draw a graph of Voltage vs Current. Determine the slope of the graph.

VOLTAGE V,(V)

VOLTAGE V, (V) vs CURRENT I, (A) 10 9 8 7 6 5 4 3 2 1 0

f(x) = 500 x R² = 1 VOLTAGE Linear (VOLTAGE)

0

0

0 0.010.010.010.010.010.020.020.02 CURRENT I,(A)

⸫ The slope of the graph is 500 which is the value of the constant resistance.

PART B – Effect of resistance changes towards the flow of current with fixed voltage

Based on your collected data in Table 1.2, draw a graph of Resistance vs Current. Determine the slope of the graph.

Resistance (Ω) vs Current I, (A) 1200

⸫ The slope of the graph is

Resistance, R (Ω)

1000

f(x) = 4.5 x^-1 R² = 1

800

4.4988 which is the value of

RESISTANCE Power (RESISTANCE) the constant

600

voltage.

400 200

6.0 DISCUSSI 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Current I, (A)

ON From the equation of

y = mx + c. -

The y-axis of the graph represent responding variable.

-

The x-axis of the graph represent manipulating variable.

-

The gradient of the graph represent the slope of the graph.

Part A is a voltage, V versus Current, I graph. As we all know the Ohm’s Law equation which V=IR. The equation displayed in the graph is y = 500x. Based on the equation, the gradient of the graph is the value of the slope obtained in PART A, which is 500. The responding variable is the voltage, V whereas the manipulating variable is the current, I. The gradient of the graph represent constant resistance, R. The graph of voltage versus current shows a straight line graph. The slope of the line is the value of the resistance. When a voltage increases, the current flow in the circuit also increases. Therefore, the current is directly proportional to the voltage.

Part B is a Resistance, R versus Current, I graph. From the Ohm’s Law equation used in the graph is

R=

V I

, which is R= VI-1. The equation displayed in the graph is y = 4.4988x -1.

Based on the equation, the gradient of the graph is the value of the slope obtained in PART B, which is 4.4988. The responding variable is the resistance, R whereas the manipulating variable is the current, I. The gradient of the graph represent constant voltage, V. The graph is a hyperbola shape. When increasing the resistance of the circuit will lower the current flow with the constant voltage. Therefore, current is inversely proportional to resistance of the circuit. 7.0 CONCLUSION After conducting this experiment, I feel I understand Ohm's Law quite clearly, and how current, resistance, and voltage are related. This relationship comes in a few forms, depending on which value we're solving for: 

Current: I=V/R



Voltage: V=I⋅R



Resistance: R=V/I

Based on the data collected and the slope calculated in the Voltage vs Current graph and the experimental value of the constant resistance was pretty accurate and that the experiment was successfully accomplished. The data collected and the slope calculated in the Resistance vs Current graph and the value of the fixed voltage was matches the expected voltage and obey Ohm’s Law. The slope obtained is the value for resistance in PART A and voltage in PART B. Ohm’s Law have been confirmed in this virtual lab experiment because of the relationship seen between current, voltage, and resistance with the information collected.

8.0 REFERENCES 8.1 http://tlaphysicsportfolio.weebly.com/ohms-law-lab.html 8.2 https://www.studocu.com/en-us/document/brooklyn-college/general-physicsii/other/ohms-law-lab-report/5933635/view 8.3 http://www.obaidtech.com/files/Courses/C1%20Lab1.pdf...