Magnetic Field (Part 1)


Understanding the concept of magnetic fields is essential in exploring the intriguing interactions that occur in the presence of magnets and currents. A magnetic field is a region surrounding a magnetic material or a moving electric charge within which the force of magnetism acts. This invisible force field plays a pivotal role in numerous phenomena, ranging from the functioning of electric motors to the behavior of compass needles aligning with Earth's magnetic field.

In the context of physics, the properties of magnetic fields are characterized by magnetic flux and magnetic flux density. Magnetic flux represents the quantity of magnetic field that penetrates a specific area, measured in units of weber (Wb). On the other hand, magnetic flux density refers to the concentration of magnetic field lines within a given region, measured in tesla (T). These parameters enable the quantification and analysis of magnetic fields in various scenarios.

When examining magnetic fields in tangible examples, the behavior of magnetic fields around different objects like permanent magnets, current-carrying conductors, and solenoids can be observed. For instance, the magnetic field around a permanent magnet forms closed loops extending from the north pole to the south pole. Similarly, the magnetic field around a current-carrying conductor demonstrates circular lines of force, emphasizing the relationship between current flow and magnetism.

In practical applications, the knowledge of magnetic fields finds utility in devices such as electric motors and moving-coil galvanometers. Electric motors leverage magnetic fields to convert electrical energy into mechanical energy, enabling the functionality of various appliances. Conversely, moving-coil galvanometers utilize magnetic fields for measuring electric currents accurately, showcasing the versatility of magnetic field concepts.

Exploring the magnetic force on current-carrying conductors reveals the fundamental interactions between magnetic fields and moving charges. When a current-carrying conductor is placed in a magnetic field, a magnetic force acts on the conductor perpendicular to both the current and the magnetic field direction. This phenomenon illustrates the dynamic nature of magnetic fields in influencing the motion of charged particles.

Furthermore, the evaluation of the magnetic force between two parallel current-carrying conductors elucidates the principles governing interactions between magnetic fields generated by currents. The interaction between these fields gives rise to attractive or repulsive forces depending on the relative directions of the currents, showcasing the intricate dynamics of magnetic field interactions.


  1. Demonstrate the magnetic force on current-carrying conductors
  2. Understand the concept of magnetic field
  3. Explain the behavior of magnetic field around different objects
  4. Calculate magnetic flux and magnetic flux density
  5. Evaluate the magnetic force between two parallel current-carrying conductors
  6. Analyze the properties of magnetic fields
  7. Apply knowledge of magnetic fields to practical applications

Lesson Note

A magnetic field is an invisible field that exerts a force on substances that are sensitive to magnetism, such as iron. It is produced by moving electric charges and intrinsic magnetic moments of elementary particles associated with a fundamental quantum property called spin. The magnetic field at any given point is specified by both a direction and a magnitude (or strength); hence it is a vector field.

Lesson Evaluation

Congratulations on completing the lesson on Magnetic Field (Part 1). Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. What is the unit of magnetic flux density? A. Watt B. Joule C. Weber D. Tesla Answer: D. Tesla
  2. Which of the following materials is not a practical example of a magnetic material? A. Aluminium B. Soft Iron C. Steel D. Alloys Answer: A. Aluminium
  3. What is the comparison between iron and steel as magnetic materials? A. Iron has higher magnetization than steel B. Steel is a temporary magnet while iron is a permanent magnet C. Steel has more resistance to corrosion compared to iron D. Iron has higher permeability than steel Answer: D. Iron has higher permeability than steel
  4. What is the SI unit of magnetic flux? A. Ohm B. Henry C. Tesla D. Weber Answer: D. Weber
  5. In which direction does the magnetic field exist around a current-carrying conductor? A. Away from the conductor B. Towards the conductor C. Along the conductor D. Perpendicular to the conductor Answer: C. Along the conductor

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Past Questions

Wondering what past questions for this topic looks like? Here are a number of questions about Magnetic Field (Part 1) from previous years

Question 1 Report

 Describe, with the aid of a diagram, how a wave can be plane polarized.

Question 1 Report

Which of the following is used for shielding radioactive fallout?

Question 1 Report

Which of the following radiations cannot be deflected by a magnetic field?

Practice a number of Magnetic Field (Part 1) past questions