TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: A vapor light produces visible light by electroluminescence process.

SOLUTION: A vapor light produces visible light by what process?

PROBLEM: Intraplate earthquakes occur because solid lithosphere travels on a round planet.

SOLUTION: What occur because solid lithosphere travels on a round planet?

PROBLEM: Speed is the term for a scalar measure of how quickly an object is moving along this line.

SOLUTION:
What is the term for a scalar measure of how quickly an object is moving along this line?