Fixed-point reference in thermometry: the internationally recognized silver point (melting point of pure silver at standard pressure) corresponds approximately to which temperature in °C?

Introduction / Context:
In temperature metrology, metal fixed points (freezing/melting points of pure metals) provide precise calibration references. The silver point is one of the high-temperature fixed points used to calibrate radiation and contact thermometers.

Given Data / Assumptions:

• Pressure is at or near 1 atm (standard atmospheric pressure).
• Pure silver in thermal equilibrium at its melting/freezing plateau.
• Approximate tabulated values are acceptable for MCQ selection.

Concept / Approach:
The silver point is commonly cited near 961 °C. For selection among rounded MCQ choices, 960.5 °C is the closest reasonable figure to the accepted value (about 961 °C), reflecting the temperature plateau observed during melting/freezing of pure silver.

Step-by-Step Solution:

Verification / Alternative check:
Calibration tables for ITS-90 list the silver point very close to 961 °C; rounding differences explain the offered 960.5 °C choice.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing the silver point (≈ 961 °C) with the gold point (≈ 1064 °C) or the antimony point (≈ 631 °C).

Final Answer:
960.5