1640. Out of 100 kcal/second of incident radiant energy on the surface of a thermally transparent body, 300 kcal/second is reflected back. If the transmissivity of the body is 0.25, the emissivity of the surface will be September 7, 2025 by Admin 0.35 0.45 0.55 0.85 ✅ The correct answer is option B.
