Answer:
It needs 46,992 m thick
Step-by-step explanation:
Copper is a metal so it has a high thermal conductivity
σ = 380 W / m K
The resistance of thermal contact between the two plates is
ρ = 0.000056 m² K / W
How conductivity and resistance are inverse
σ_plate = 1 /ρ
σ_plate = 1 / 0.000056
σ_plate = 17857.14 W / K m²
Let's look for the relationship between the two magnitudes
σ-Plate / σ_cupper = 17857.14 / 380
σ_plate / σ_cupper = 46,992 m
It needs 46,992 m thick