(4ai) Diagram (4aii) (i) Inner Cone: This is the hottest part of the flame, where the acetylene and oxygen combine. (ii) Outer Cone/envelope: This surrounds the inner cone and is less hot. (4b) One factor to consider when choosing a cutting nozzle is the thickness of the material to be cut. The nozzle size must match the material thickness to ensure a clean and efficient cut. (4c) Diagram 👇🏻👇🏻👇🏻👇🏻