Question

1. a) Compare and contrast magnetic and electric fields. Your answer should include at least 2 ways they are similar and 2 ways that they differ.

b) Include a diagram of an electric field for either a positive or negative point charge and a diagram for a typical bar magnet. Make sure you show the field lines (including direction) and label the charges and poles.

Answer 1

Answer 2

Comparison of Magnetic and Electric Fields

Similarities:

1. Both are Fundamental Force Fields:

• Electric fields arise from electric charges (stationary or moving).

• Magnetic fields arise from moving charges (currents) or intrinsic magnetic dipoles (e.g., electrons).

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2. Field Lines Represent Strength/Direction:

• Electric: Lines point away from (+) charges and toward (−) charges.

• Magnetic: Lines form closed loops from North (N) to South (S) poles.

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Differences:

1. Source of Field:

• Electric: Requires isolated charges (monopoles, e.g., +q or −q).

• Magnetic: No isolated monopoles; always dipolar (N and S poles coexist).

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2. Force Interaction:

• Electric: Acts on any charged particle (stationary or moving).

• Magnetic: Only acts on moving charges (Lorentz force: $\vec{F}=q\vec{v}\times \vec{B}$).

Diagrams

1. Electric Field of a Point Charge

• Positive Charge: Field lines radiate outward.

• Negative Charge: Field lines point inward.

  
  

  (+) Charge       (−) Charge  
    ↖↑↗              ↙↓↘  
    ←⊕→              →⊖←  
    ↙↓↘              ↖↑↗

2. Magnetic Field of a Bar Magnet

• Field lines emerge from N pole and enter S pole.

  
  

  N ―――――――→ S  
  ◀━━━━━━━━━▶

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