Which statement is true about poor conductors when conducting current?

The statement that poor conductors can glow red or white hot is accurate because poor conductors have a high resistance to the flow of electric current. When electrical current passes through a material with high resistance, it generates heat due to the collisions between moving electrons and the atoms in the material. This heat can raise the temperature of poor conductors to the point where they begin to emit visible light, appearing red or even white hot, as their temperature increases.

In contrast, other options present different scenarios regarding electrical conduction and resistance. For instance, saying they remain cold is inaccurate because, as explained, poor conductors can heat up significantly when conducting current. The assertion that they have no effect on electrical flow is also misleading, as poor conductors actually impede the flow of electricity, creating resistance that affects overall circuit performance. Finally, stating that they are always insulators oversimplifies the concept, as insulators are materials specifically designed to resist electrical current to an extreme degree, while poor conductors do still allow some degree of current flow, albeit inefficiently. Thus, the phenomenon of poor conductors glowing under current makes the selected statement the most accurate in the context provided.