Co-efficient of Thermal exansion of amalgam is______________? September 27, 2025 by Admin A. 6.6 a (ppm k-1) B. 11.4 a (ppm k-1) C. 14.0 a (ppm k-1) D. 25.0 a (ppm k-1) ✅ The correct answer is option D. 25.0 a (ppm k-1).