Which term describes a material that changes colour in response to light?

Which term describes a material that changes colour in response to light?

• A. Photochromicity
• B. Photochromism
• C. Thermochromism
• D. Fluorescence

Answer: (A)

Light-induced color change describes the property of a material that shifts color when illuminated. Photochromicity names that property—the material has the ability to change color under light, due to reversible changes in its structure or electronic state. The observable phenomenon is photochromism, but the term describing the material’s capability is photochromicity, making it the best fit for this description. The other ideas refer to different triggers or effects: thermochromism is color change with temperature, and fluorescence is the emission of light after absorbing energy, not a reversible color change of the material’s appearance.

Light-induced color change describes the property of a material that shifts color when illuminated. Photochromicity names that property—the material has the ability to change color under light, due to reversible changes in its structure or electronic state. The observable phenomenon is photochromism, but the term describing the material’s capability is photochromicity, making it the best fit for this description. The other ideas refer to different triggers or effects: thermochromism is color change with temperature, and fluorescence is the emission of light after absorbing energy, not a reversible color change of the material’s appearance.