3 Sig FIgs in 303,000 mm
Any nonzero is a sig fig.
Any zero between two non zeros is a sig fig.
Sound is a form of energy is incorrect
Sound is caused by the movement or vibration of matter
The residue of coal decomposition in the manufacture of steel is coal tar. It is a by product of the coking process in the blast furnace. Coal gas is another by product but is not the answer becuase this is not a residue which is a solid. Coal gas is a gas. Coke in fact is one of the reactants fed for steel making. Answer is choice 3.
