The value of the ITC ranges from ______ and is defined by what 2 equations?

• A. 0% to 100%; ITC (%) = Transmitted Intensity/Incident Intensity x 100; ITC (%) = 1 - IRC
• B. -0% to 100%; ITC (%) = Transmitted Intensity/Incident Intensity x 100; ITC (%) = 1 - IRC
• C. -100% to 100%; ITC (%) = Transmitted Intensity/Incident Intensity x 100; ITC (%) = 1 - IRC
• D. 0% to 100%; ITC (%) = Incident Intensity/Transmitted x 100; ITC (%) = 1 - IRC

Answer: (C)

ITC measures what portion of the incoming light actually gets through, expressed as a percent. It is found by dividing the transmitted intensity by the incident intensity and multiplying by 100, giving ITC as the percent of incident light that is transmitted. The second relation ties ITC to IRC: ITC equals 1 minus IRC. That reflects an energy-balance idea: the portion not reflected is what can be transmitted (under the conventions used in this material). Together, these two equations define ITC from both a direct transmission ratio and as a complement to the reflected portion. The range given here is -100% to 100%, which follows the material’s convention for IRC; in typical optics you’d usually see ITC range from 0% to 100%.