(Emissivity and temperature change combined) A cast-iron plate of area initially has…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
(Emissivity and temperature change combined)
A cast-iron plate of area 0.50m2 initially has an emissivity of 0.60 and is maintained at 900K. It is later coated with a special paint that increases its emissivity to 0.90, while at the same time the plate cools to 750K. Keeping all other conditions identical, answer the following.
(i) Obtain the ratio of the final total power radiated by the plate to its initial power.
(ii) Express the change in power as a percentage increase or decrease relative to the initial value.