Induced drag is the result of an airfoil developing lift. Which option best describes this statement?

• A. The drag caused by the engine cowlings and antennas
• B. The drag that arises from lift on an airfoil
• C. The drag due to interference between surfaces
• D. The drag due to skin friction

Answer: (B)

Induced drag is the drag that appears as a byproduct of producing lift. When a wing generates lift, it deflects air downward and creates wingtip vortices. Energy is spent to create that downward deflection and the associated wake, and part of that energy shows up as a resisting force along the flight path—that is induced drag.

The option that describes drag arising from lift on an airfoil matches this idea precisely: it’s the drag created specifically because the wing is producing lift. The other choices describe drag sources not tied to lift production—parasite drag from components like engine cowlings and antennas, drag from interference between surfaces, and skin-friction drag from viscous shear. Those are important parts of total drag, but they’re not induced by lift.

A useful context: induced drag is typically higher at lower speeds and high angles of attack because the wing must generate more lift (more circulation and stronger downwash), increasing energy put into the wake. As speed increases, induced drag decreases while parasite drag becomes more prominent.