According to ITT note #1, a linear variation applies above which temperatures for ten seconds and two seconds respectively?

According to ITT note #1, a linear variation applies above which temperatures for ten seconds and two seconds respectively?

• A. 980-1090 °C (2 sec); 1090 °C max
• B. 755-810 °C; 810 °C max
• C. 860 °C (5 sec)
• D. 870 °C; 980 °C

Answer: (D)

The question tests the two-threshold timing concept: there are two temperature points where a linear variation applies, each with its own exposure time. The first threshold is 870 °C and must be held for ten seconds, and the second threshold is 980 °C and must be held for two seconds. The option that lists 870 °C and 980 °C in the order corresponding to ten seconds and two seconds matches this two-tier requirement from ITT note #1, so it aligns with the given timings exactly. Other options propose different temperatures, ranges, or a single threshold, which don’t fit the described two-step timing pattern.

The question tests the two-threshold timing concept: there are two temperature points where a linear variation applies, each with its own exposure time. The first threshold is 870 °C and must be held for ten seconds, and the second threshold is 980 °C and must be held for two seconds. The option that lists 870 °C and 980 °C in the order corresponding to ten seconds and two seconds matches this two-tier requirement from ITT note #1, so it aligns with the given timings exactly. Other options propose different temperatures, ranges, or a single threshold, which don’t fit the described two-step timing pattern.