A laboratory wall is built from a material with thermal conductivity k. The wall currently has cross-sectional area A0 and thickness L0. The laboratory manager wants to modify only the geometric dimensions so that the rate of thermal energy conduction through the wall is exactly one-half its present value, while the temperature difference across the wall remains unchanged. Which single alteration will achieve this goal?
a) Double the cross-sectional area to 2A0 while keeping the thickness L0 unchanged.
b) Halve the thickness to 21L0 while keeping the area A0 unchanged.
c) Double the thickness to 2L0 while keeping the area A0 unchanged.
d) Increase the thickness to 2L0 while keeping the area A0 unchanged.