Final answer:
The range of minimum radiative flux to make a solid ignitable by a pilot flame is 200 to 500 kW/m².
Step-by-step explanation:
The range of minimum radiative flux that must impinge on a solid to make it ignitable by a pilot flame depends on various factors such as the material of the solid and the conditions of the environment. However, in general, a radiative flux of at least 200 to 500 kW/m² is required to ignite a solid.
Therefore, the correct answer is option D) 200 to 500 kW/m². This range of radiative flux provides enough heat to start a combustion reaction.
The range of minimum radiative flux that must impinge on a solid to make it ignitable by a pilot flame is typically between 50 to 100 kW/m². This is a concept that falls under the study of thermodynamics and heat transfer in physics.