Please can anybody tell me what is this lab equipment

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

Thermal radiation gets its name because