# Are these statements about different emissivities correct?

I'd like to verify if my concluded statements regarding different emissivities are correct or not. And if not, why.

1

Two objects, one with an emissivity of 1 (object A) and one with a very low emissivity (object B), sitting in a room, everything at the same temperature T. Object A has the same T because it’s absorbing and emitting an equal high energy. Object B has the same T because it’s absorbing and emitting an equal low energy. Object A is therefore emitting more energy than object B. However, because object B has a low emissivity, it reflects the rest of the radiation coming from the surroundings. This means that the energy that object B is emitting + reflecting is equal to the energy that object A is emitting. A detector would therefore (falsely) measure that they both are giving off an equal amount of energy.

2

Now objects A and B have the same T but are in a room that is hotter (thus not thermal equilibrium). Object A would therefore emit less energy than it absorbs. Object B would do the same albeit the energy that object B absorbs and emits is less than that of A. Object A would therefore emit more energy than object B. However, object B directly reflects the non-absorbed radiation coming from the hotter surrounding. A detector would therefore (falsely) show that object B is giving off more energy than object A.

3

Now objects A and B have the same T but in a colder room. Object A is emitting more energy than it absorbs. Object B is doing the same albeit the energy that it absorbs and emits is lower than that of object A. Object A is therefore emitting more energy than object B. Since B is a good reflector, it also reflects the low energy (that B didn’t absorb) coming from the colder surrounding. Therefore, B is emitting a low energy based on its T + reflecting a low energy from the cold surrounding and A is emitting a high energy based on the same T but doesn’t reflect energy. This doesn’t necessarily mean that B is giving off more energy than A according to a detector and depends on the emissivity of B and on the emissivity and temperature of the surroundings.