Leaving the carburetor heat on while taking off will have what effect?

Leaving the carburetor heat on during takeoff causes the mixture entering the engine to be richer than optimal for performance. Carburetor heat is designed to prevent ice formation in the carburetor; however, when activated, it introduces warm air, which decreases the air density and creates a richer fuel-to-air ratio. This richer mixture reduces engine efficiency and overall power output.

As a result, the aircraft may experience an increase in ground roll during takeoff. The engine's reduced power means that it cannot generate as much thrust, leading to a longer distance required to reach the necessary speed for liftoff. Therefore, keeping the carburetor heat on will hinder performance, resulting in an increased ground roll, making this answer correct.

Understanding this effect is important for flight safety and ensuring optimal aircraft performance during critical phases such as takeoff.