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True airspeed (TAS) compared to indicated airspeed (IAS) at altitude is generally

Choices

lower at high altitude.
Reversed — TAS is HIGHER at altitude.
✓ higher at high altitude.correct
TAS increases ~2% per 1,000 ft above sea level under standard conditions, because lower air density means the IAS undersamples the actual airspeed. IAS is what the pitot-static reads from dynamic pressure. As altitude increases and air thins, the same dynamic pressure represents a higher TRUE airspeed. Rule of thumb: TAS ≈ IAS × (1 + 0.02 × altitude/1000) under ISA. At 10,000 ft, TAS is roughly 18-20% higher than IAS.
the same regardless of altitude.
TAS varies with density.
exactly equal at 10,000 ft.
10,000 ft has TAS ~20% above IAS.

Why

TAS increases ~2% per 1,000 ft above sea level under standard conditions, because lower air density means the IAS undersamples the actual airspeed. IAS is what the pitot-static reads from dynamic pressure. As altitude increases and air thins, the same dynamic pressure represents a higher TRUE airspeed. Rule of thumb: TAS ≈ IAS × (1 + 0.02 × altitude/1000) under ISA. At 10,000 ft, TAS is roughly 18-20% higher than IAS.

FAA source: PHAK Ch 8, Ch 11; PHAK Chapter 8 — Flight Instrumentsbrowse the reference library →

Covered in Supplemental · V — Performance and Ground Reference Maneuvers — study the lessons free, then practice with grading and mastery tracking.

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.