Magnetic Field

• The magnetic field around a current-carrying straight conductor is a region where magnetic forces are experienced.
• It is represented by the symbol “B” and is measured in Tesla (T).
• The magnetic field is a vector quantity, which means it has both magnitude and direction.
• The direction of the magnetic field lines is given by the right-hand rule.

Biot-Savart Law

• The Biot-Savart Law helps us calculate the magnetic field produced by a current-carrying straight conductor.
• It states that the magnetic field at a point due to an infinitesimally small current element is directly proportional to the current and inversely proportional to the distance from the point to the element.
• Mathematically, the Biot-Savart Law is expressed as:
  • dB = (μ₀ / 4π) * (Idl × r) / r³
• Where:
  • dB is the magnetic field at the point,
  • μ₀ is the permeability of free space,
  • Idl is the current element,
  • r is the distance from the point to the current element.

Magnetic Field Due to a Straight Conductor

• Consider a straight conductor carrying current “I”.
• We can calculate the magnetic field at a distance “r” from the conductor using the Biot-Savart Law.
• The direction of the magnetic field is given by the right-hand rule.
• Example:

  • Consider a straight conductor carrying 5 A of current.

  • Calculate the magnetic field at a distance of 10 cm from the conductor.

  • Solution:

    • Using the Biot-Savart Law, we can calculate the magnetic field as follows:
      • dB = (μ₀ / 4π) * (I * dl × r) / r³
      • dB = (4π × 10^-7 T m/A) * (5 A * dl × 0.1 m) / (0.1^2 m³)
      • dB = (2 × 10^-6 T) * (dl / 0.01 m)

Magnetic Field Due to a Straight Conductor (contd.)

• Example (contd.):
  • To find the magnetic field at a distance “r”, we need to integrate the magnetic field expression over the length of the conductor.
  • Let’s assume the length of the conductor is “L”.
  • The magnetic field at a distance “r” due to the entire conductor is the sum of the contributions from all infinitesimally small current elements.
• Equation:
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³, from 0 to L

Ampere’s Law

• Ampere’s Law relates the magnetic field around a closed loop to the current passing through the loop.
• It states that the line integral of the magnetic field, B, around a closed loop is equal to μ₀ times the total current enclosed by the loop.
• Mathematically, Ampere’s Law is expressed as:
  • ∮B * dl = μ₀ * I_enclosed
• Where:
  • ∮B * dl is the line integral of the magnetic field around the closed loop,
  • μ₀ is the permeability of free space,
  • I_enclosed is the total current enclosed by the loop.

Ampere’s Law (contd.)

• Ampere’s Law is extremely useful for calculating the magnetic field around simple geometric shapes with symmetry.
• It simplifies the calculation process by utilizing the concept of symmetry to find the magnetic field.
• Ampere’s Law is a fundamental tool in understanding and predicting the behavior of magnetic fields in various situations.
• Next, we will explore some examples and applications of Ampere’s Law in real-life scenarios.

Note: Please continue with the remaining slides.

Magnetic Field For A Straight Conductor And Ampere’s Law - Biot-Savart Law

• In this lecture, we will discuss the concept of magnetic fields and Ampere’s Law in relation to straight conductors.
• We will explore how to calculate the magnetic field around a straight conductor using the Biot-Savart Law.
• Understanding these concepts is crucial for understanding the behavior of magnetic fields in various situations.
• Let’s begin by revisiting the definition of a magnetic field. = Magnetic Field =
• The magnetic field around a current-carrying straight conductor is a region where magnetic forces are experienced.
• It is represented by the symbol “B” and is measured in Tesla (T).
• The magnetic field is a vector quantity, which means it has both magnitude and direction.
• The direction of the magnetic field lines is given by the right-hand rule.

= Biot-Savart Law =

• The Biot-Savart Law helps us calculate the magnetic field produced by a current-carrying straight conductor.
• It states that the magnetic field at a point due to an infinitesimally small current element is directly proportional to the current and inversely proportional to the distance from the point to the element.
• Mathematically, the Biot-Savart Law is expressed as:
  • dB = (μ₀ / 4π) * (Idl × r) / r³
• Where:
  • dB is the magnetic field at the point,
  • μ₀ is the permeability of free space,
  • Idl is the current element,
  • r is the distance from the point to the current element.

= Magnetic Field Due to a Straight Conductor =

• Consider a straight conductor carrying current “I”.
• We can calculate the magnetic field at a distance “r” from the conductor using the Biot-Savart Law.
• The direction of the magnetic field is given by the right-hand rule.
• Example:

  • Consider a straight conductor carrying 5 A of current.

  • Calculate the magnetic field at a distance of 10 cm from the conductor.

  • Solution:

    • Using the Biot-Savart Law, we can calculate the magnetic field as follows:
      • dB = (μ₀ / 4π) * (I * dl × r) / r³
      • dB = (4π × 10^-7 T m/A) * (5 A * dl × 0.1 m) / (0.1^2 m³)
      • dB = (2 × 10^-6 T) * (dl / 0.01 m)

= Magnetic Field Due to a Straight Conductor (contd.) =

• Example (contd.):
  • To find the magnetic field at a distance “r”, we need to integrate the magnetic field expression over the length of the conductor.
  • Let’s assume the length of the conductor is “L”.
  • The magnetic field at a distance “r” due to the entire conductor is the sum of the contributions from all infinitesimally small current elements.
• Equation:
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³, from 0 to L

= Ampere’s Law =

• Ampere’s Law relates the magnetic field around a closed loop to the current passing through the loop.
• It states that the line integral of the magnetic field, B, around a closed loop is equal to μ₀ times the total current enclosed by the loop.
• Mathematically, Ampere’s Law is expressed as:
  • ∮B * dl = μ₀ * I_enclosed
• Where:
  • ∮B * dl is the line integral of the magnetic field around the closed loop,
  • μ₀ is the permeability of free space,
  • I_enclosed is the total current enclosed by the loop. = Ampere’s Law (contd.) =
• Ampere’s Law is extremely useful for calculating the magnetic field around simple geometric shapes with symmetry.
• It simplifies the calculation process by utilizing the concept of symmetry to find the magnetic field.
• Ampere’s Law is a fundamental tool in understanding and predicting the behavior of magnetic fields in various situations.
• Next, we will explore some examples and applications of Ampere’s Law in real-life scenarios.

Magnetic Field For A Straight Conductor And Ampere’s Law - Biot-Savart Law

• In this lecture, we will discuss the concept of magnetic fields and Ampere’s Law in relation to straight conductors.
• We will explore how to calculate the magnetic field around a straight conductor using the Biot-Savart Law.
• Understanding these concepts is crucial for understanding the behavior of magnetic fields in various situations.
• Let’s begin by revisiting the definition of a magnetic field.

Magnetic Field

• The magnetic field around a current-carrying straight conductor is a region where magnetic forces are experienced.
• It is represented by the symbol “B” and is measured in Tesla (T).
• The magnetic field is a vector quantity, which means it has both magnitude and direction.
• The direction of the magnetic field lines is given by the right-hand rule.

Biot-Savart Law

• The Biot-Savart Law helps us calculate the magnetic field produced by a current-carrying straight conductor.
• It states that the magnetic field at a point due to an infinitesimally small current element is directly proportional to the current and inversely proportional to the distance from the point to the element.
• Mathematically, the Biot-Savart Law is expressed as:
  • dB = (μ₀ / 4π) * (Idl × r) / r³
• Where:
  • dB is the magnetic field at the point,
  • μ₀ is the permeability of free space,
  • Idl is the current element,
  • r is the distance from the point to the current element.

Magnetic Field Due to a Straight Conductor

• Consider a straight conductor carrying current “I”.
• We can calculate the magnetic field at a distance “r” from the conductor using the Biot-Savart Law.
• The direction of the magnetic field is given by the right-hand rule.
• Example:

  • Consider a straight conductor carrying 5 A of current.

  • Calculate the magnetic field at a distance of 10 cm from the conductor.

  • Solution:

    • Using the Biot-Savart Law, we can calculate the magnetic field as follows:
      • dB = (μ₀ / 4π) * (I * dl × r) / r³
      • dB = (4π × 10^-7 T m/A) * (5 A * dl × 0.1 m) / (0.1^2 m³)
      • dB = (2 × 10^-6 T) * (dl / 0.01 m)

Magnetic Field Due to a Straight Conductor (contd.)

• Example (contd.):
  • To find the magnetic field at a distance “r”, we need to integrate the magnetic field expression over the length of the conductor.
  • Let’s assume the length of the conductor is “L”.
  • The magnetic field at a distance “r” due to the entire conductor is the sum of the contributions from all infinitesimally small current elements.
• Equation:
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³
  • B = (μ₀ / 4π) * (I * ∫ dl × r) / r³, from 0 to L

Ampere’s Law

• Ampere’s Law relates the magnetic field around a closed loop to the current passing through the loop.
• It states that the line integral of the magnetic field, B, around a closed loop is equal to μ₀ times the total current enclosed by the loop.
• Mathematically, Ampere’s Law is expressed as:
  • ∮B * dl = μ₀ * I_enclosed
• Where:
  • ∮B * dl is the line integral of the magnetic field around the closed loop,
  • μ₀ is the permeability of free space,
  • I_enclosed is the total current enclosed by the loop.

Ampere’s Law (contd.)

• Ampere’s Law is extremely useful for calculating the magnetic field around simple geometric shapes with symmetry.
• It simplifies the calculation process by utilizing the concept of symmetry to find the magnetic field.
• Ampere’s Law is a fundamental tool in understanding and predicting the behavior of magnetic fields in various situations.
• Next, we will explore some examples and applications of Ampere’s Law in real-life scenarios.

Ampere’s Law - Applications

• Ampere’s Law is widely used in various applications to calculate magnetic fields and understand their behavior. Some important applications include:

1. Solenoids
   • Ampere’s Law allows us to determine the magnetic field produced by a current-carrying solenoid.
   • It enables us to calculate the magnetic field strength inside and outside the solenoid.
   • This is crucial for the design and optimization of solenoid-based devices such as electromagnets and inductors.

2. Toroids
   • An application of Ampere’s Law is in determining the magnetic field produced by a toroid.
   • A toroidal coil is a circular loop of wire wound in a helical path.
   • Ampere’s Law helps us calculate the magnetic field inside and outside the toroid, which is important in applications like transformers and magnetic confinement in plasma physics.

3. Magnetic Field of Current Loop
   • Ampere’s Law allows us to calculate the magnetic field at any point due to a current-carrying loop.
   • This is important in understanding the behavior of magnets, magnetic dipole moments, and magnetic resonance imaging (MRI).

4. Magnetic Field of Straight Conductors
   • We can use Ampere’s Law to calculate the magnetic field around straight conductors, which is useful in various applications such as determining the magnetic field around power lines and calculating the forces experienced by current-carrying wires.

5. Magnetic Field of Current Sheets
   • Ampere’s Law can be used to find the magnetic field produced by current sheets, which are flat surfaces carrying a uniform distribution of current.
   • This is important in applications like magnetic shielding and the design of devices using superconducting materials.

• These are just a few examples of how Ampere’s Law is applied in real-world scenarios to understand and manipulate magnetic fields.

Summary

• In this lecture, we discussed the magnetic field for a straight conductor and Ampere’s Law.
• We revisited the definition of the magnetic field and understood its significance in studying magnetic phenomena.
• We explored the Biot-Savart Law, which helps us calculate the magnetic field produced by a straight conductor.
• Using examples, we learned how to calculate the magnetic field at a specific distance from a straight conductor.
• We also discussed Ampere’s Law, which relates the magnetic field around a closed loop to the current passing through the loop.
• Ampere’s Law has several applications, such as calculating the magnetic field produced by solenoids, toroids, and current loops.
• Understanding these concepts is essential for comprehending magnetic fields and their behavior in different situations.
• Practice solving problems and working on examples to strengthen your understanding of these topics.

References

• Insert reference materials and resources here.

Solenoids

• A solenoid is a long, tightly wound coil of wire used to generate a uniform magnetic field.
• The magnetic field inside a solenoid is nearly constant and parallel to the axis of the solenoid.
• The magnetic field outside the solenoid is negligible.
• The strength of the magnetic field inside a solenoid depends on the number of turns per unit length, the current flowing through the solenoid, and the permeability of the material inside the solenoid.

Toroids

• A toroid is a hollow, circular loop of wire wound in a helical path, similar to a donut shape.
• The magnetic field inside a toroid is strong and nearly uniform.
• The magnetic field outside the toroid is negligible.
• The strength of the magnetic field inside a toroid depends on the number of turns, the current flowing through the toroid, and the average radius of the toroid.

Magnetic Field of Current Loop

• The magnetic field at the center of a circular current loop is given by the equation:
  • B = (μ₀ * I * R²) / (2 * (R² + z²)^(3/2))
• Where:
  • B is the magnetic field at the center,
  • μ₀ is the permeability of free space,
  • I is the current flowing through the loop,
  • R is the radius of the loop,
  • z is the distance from the center of the loop.

Magnetic Field of Straight Conductors

• The magnetic field produced by a long, straight conductor can be calculated using Ampere’s Law.
• For a conductor of infinite length, the magnetic field at a distance “r” from the conductor is given by the equation:
  • B = (μ₀ * I) / (2 * π * r)
• Where: