Introduction
Studying the magnetic field generated by a coil is fundamental for understanding many aspects of Physics, especially in relation to electricity and magnetism. The magnetic field is a region of space around a magnet or an electric current where magnetic field lines circulate. Coils, also known as inductors or solenoids, are made up of a sequence of turns of a conductor wire, which generate a magnetic field when an electric current flows through them.
Calculating the magnetic field inside a coil is particularly important, as the intensity of this field depends on factors such as the number of turns of the coil and the current flowing through it. Ampère's law is the theoretical tool that allows us to calculate this field, and the development of this project will provide you with a deeper understanding of this law and its applications.
The study also involves concepts such as magnetic flux, which is directly proportional to the number of magnetic field lines crossing a certain surface. In addition, we will also address Faraday-Neumann-Lenz's law, which establishes how a variation in magnetic flux can generate an electric current in a closed circuit.
Contextualization
Coils are used in numerous technical and scientific applications in modern life. For example, coils are found in voltage transformers, used in all households to adapt the electrical voltage coming from transmission lines to the needs of various electrical appliances. They are also employed in electric motors and generators, magnetic resonance imaging devices, car ignition systems, and even in radio and television antennas.
Understanding the magnetic field generated by a coil is therefore essential both for basic education in Physics and for understanding the operation of the various technological devices we use in our daily lives. By the end of this project, you will be able to calculate the magnetic field generated by a coil and understand how this concept is applied in practice.
To support the completion of this project, we suggest consulting the book 'Physics for Scientists and Engineers' by Serway and Jewett, which addresses the topic concisely and didactically. Online, a valuable resource is the 'Brasil Escola' website, which presents a series of articles on the subject with detailed explanations and practical examples. Additionally, the 'Ciência em Ação' channel on YouTube offers a series of explanatory videos on the topic.
Physics for Scientists and Engineers, Serway and Jewett
Practical Activity
Activity Title: 'Exploring the Magnetic Field Generated by a Coil'
Project Objective
The main objective of this project is to calculate and analyze the magnetic field generated by a coil.
Detailed Project Description
In this project, students will build a simple coil and use a multimeter to measure the magnetic field it generates. Subsequently, they will vary the intensity of the current flowing through it and the number of turns of the coil, observing how these parameters affect the intensity of the generated magnetic field.
It is expected that students work in groups of 3 to 5 people and that the project execution takes 5 to 10 hours per student, spread over a month.
Required Materials
- Enamel copper wire
- Cardboard tube (can be an empty toilet paper roll or paper towel roll)
- Adhesive tapes
- 9V battery
- Multimeter with magnetic field measuring function
- Tape measure or ruler
Activity Steps
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Wind the copper wire around the cardboard tube to form a coil. Start with about 10 turns and secure the ends with adhesive tape.
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Connect the coil to the battery using two pieces of copper wire, one at each end of the coil.
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Using the multimeter, measure the magnetic field generated by the coil when the battery current flows through it. Record this value.
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Remove the battery and add another 10 turns to the coil. Reconnect the battery and measure the new magnetic field generated.
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Repeat step 4 until you have made at least 5 measurements with different numbers of turns in the coil.
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Now, keeping the number of turns in the coil constant, vary the intensity of the current flowing through it. Do this by changing the 9V battery for others with different voltages (if available) or by inserting resistors in the circuit to decrease the current.
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Measure and record the magnetic field generated by the coil for each current value used.
Project Deliverables
The main product of this project is a detailed report on the experiment conducted. The report should include:
1. Introduction
In the introduction, the group should state the project's objective, briefly explain the concept of the magnetic field and the importance of studying this phenomenon, its practical applications, and the elementary theory of the coil as a magnetic field generator.
2. Development
In the development, the group should detail the experiment setup, describing all the steps followed and the materials used. All the theory used should be explained at this point, including Ampère's law and how it was applied to calculate the coil's magnetic field. Additionally, in this section, the group should present the collected data, the generated tables, and the graphs created to facilitate the visualization of the results.
3. Conclusion
In the conclusion, students should summarize the main points addressed in the work, relate the results obtained to the theoretical predictions, mention whether the predictions were confirmed or not and why. They should also discuss possible sources of error and, if applicable, what could be done to improve the experiment in the future.
4. Bibliography
All sources consulted during the project development should be listed. Books, articles, websites, and videos used for understanding the theory and for the experiment's elaboration should be included here.
By the end of this project, students will be able to calculate and understand the relationship between current, number of turns, and the magnetic field generated by a coil, as well as develop time management, communication, problem-solving, creative thinking, proactivity, and teamwork skills.
