Question E3A08:
When a meteor strikes the Earth’s atmosphere, a linear ionized region is formed at what region of the ionosphere?  

Choices:  
A: The E region  
B: The F1 region  
C: The F2 region  
D: The D region    

Correct Answer is  A: The E region  

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Meteors ablate and ionize the air at altitudes where the E region resides. The ionized “trail” they leave is thus in the E region and can reflect/forward-scatter VHF signals for short bursts.

Why the correct answer (E region) is correct:
- The E region is roughly $90$–$120\ \text{km}$ altitude.
- Meteors typically ablate and produce dense, elongated ionized trails around $80$–$120\ \text{km}$, peaking near $90$–$110\ \text{km}$—right in the E region.

Why the other choices are incorrect:
- D region ($\sim 60$–$90\ \text{km}$): Too low and very lossy; high recombination and collision rates rapidly quench ionization. Most meteors fully ablate higher up.
- F1 region ($\sim 150$–$200\ \text{km}$, daytime): Too high for the bulk of meteor ablation; F1 ionization is solar-driven, not meteor-produced.
- F2 region ($\sim 200$–$400+\ \text{km}$): Also solar-driven and much higher than typical meteor trails.

Useful rules of thumb:
- Ionospheric layer heights (daytime approx):
  - D: $60$–$90\ \text{km}$
  - E: $90$–$120\ \text{km}$
  - F1: $150$–$200\ \text{km}$
  - F2: $200$–$400+\ \text{km}$
- Meteor-scatter communications:
  - Most effective at $30$–$150\ \text{MHz}$ (often $50$–$150\ \text{MHz}$).
  - Typical single-burst durations: milliseconds to a few seconds.
  - Typical one-hop distances: roughly $500$–$1400\ \text{km}$.

So, the ionized line from a meteor is in the E region.