Answer:
The temperature is 2584.5 K
Step-by-step explanation:
Given:
Activation energy

Preexponential

Diffusion flux

Thickness of plate
m
Concentration of carbon at two faces

From the formula of temperature in terms of diffusion flux,

Where
8.314
( gas constant )
Put the values and find the temperature,

K
Therefore, the temperature is 2584.5 K