The correct option is (b) W/dtC√2gh
Easiest explanation: Choke area (A) = W/dtC√2gh, It is the main control area which meters the metal flow into the mould cavity so that the mould is completely filled within the calculated pouring time. Its unit is mm².
Where, W = Casting mass (kg), t = pouring time (second), d = mass density (kg/mm³),
h = Sprue height (mm), g = Acceleration due to gravity (mm/s²), C = Efficiency factor.
