[scientizscht (OP)]

Hello

Two cylinders with the same volume but different radius, have the same surface area?

If not, how much is the difference between two 5mL cylinders with radius 10mm and 1mm?

[Bored chemist]

Two cylinders with the same volume but different radius, have the same surface area?

No

If not, how much is the difference between two 5mL cylinders with radius 10mm and 1mm?

What did  your last slave die of?

Incidentally,
"What is the 3D shape with the maximum surface area?"
This sort of thing.
https://en.wikipedia.org/wiki/Menger_sponge#Similar_fractals

[chiralSPO]

It's quite easy to find the surface area of a cylinder:

the top and bottom circle are the same, each having area: where r is the radius of the cylinder

and the outside is just where h is the height of the cylinder

[CPT ArkAngel]

What is the best design for a heatsink?

[evan_au]

This one: https://en.wikipedia.org/wiki/Heat_pipe

Of course, that only defers the problem, as the heat pipe needs a cold sink...

[alancalverd]

There is no single best design. The optimum design depends on the nature of the heat loading, the specified temperature excursion limits of the source, the nature and availability of the cold source, and a whole load of other considerations. Liquid sodium is an excellent conductor in exhaust valves and nuclear reactors, but isn't everyone's cup of tea.