Edexcel iGCSE Physics -6.7 Uniform Magnetic Fields- Study Notes- New Syllabus

Edexcel iGCSE Physics -6.7 Uniform Magnetic Fields- Study Notes- New syllabus

Edexcel iGCSE Physics -6.7 Uniform Magnetic Fields- Study Notes -Edexcel iGCSE Physics – per latest Syllabus.

Key Concepts:

6.7 describe how to use two permanent magnets to produce a uniform magnetic field pattern

Edexcel iGCSE Physics -Concise Summary Notes- All Topics

Producing a Uniform Magnetic Field Using Two Permanent Magnets

A uniform magnetic field is a magnetic field that has the same strength and same direction at every point in a region. This type of field can be produced using two permanent bar magnets arranged in a specific way.

Uniform Magnetic Field – Meaning

Definition: A magnetic field is uniform if the magnetic field lines are:

  • Parallel
  • Equally spaced
  • Pointing in the same direction

Key idea: Uniform fields are shown by straight, evenly spaced field lines.

Arrangement of Two Permanent Magnets

To produce a uniform magnetic field:

  • Use two identical bar magnets.
  • Place them close together.
  • Arrange them with unlike poles facing each other (N facing S).
  • Ensure the magnets are parallel and aligned.

Result: The magnetic field lines between the facing poles become straight and evenly spaced, producing a uniform magnetic field in that region.

Why This Arrangement Produces a Uniform Field

  • Field lines leave the north pole and enter the south pole.
  • Between unlike poles, field lines join smoothly.
  • The closeness and parallel alignment keep spacing constant.
  • This creates a region where field strength and direction are constant.

Important note: The field is only approximately uniform in the central region between the magnets.

How to Investigate the Field Pattern

  • Place paper over the arranged magnets.
  • Sprinkle iron filings evenly.
  • Tap gently to reveal the pattern.
  • Look for straight, parallel, evenly spaced lines.

What Happens If Like Poles Are Used?

  • Field lines repel and curve away.
  • Spacing is uneven.
  • No uniform field is formed.

Key idea: Uniform magnetic fields cannot be produced using like poles.

Example

Two identical bar magnets are placed with their north and south poles facing each other and a small gap between them. Iron filings show straight, evenly spaced lines in the central region. Explain why this region represents a uniform magnetic field.

▶️ Answer / Explanation
  • Straight field lines show constant direction.
  • Even spacing shows constant field strength.
  • The field lines join from north to south.
  • This combination indicates a uniform magnetic field.

Example

A student tries to produce a uniform magnetic field by placing two bar magnets with their north poles facing each other. The field pattern is uneven. Explain why this arrangement does not produce a uniform magnetic field.

▶️ Answer / Explanation
  • Like poles repel.
  • Magnetic field lines bend away from each other.
  • The spacing between field lines is uneven.
  • The direction of the field changes across the region.
  • This means the field is not uniform.
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