Petrol low warning light on Vauxhall Corsa question

[Dennis W]

If we put petrol in the tank while the Petrol low warning light has illuminated, and then we drive on, the petrol low light doesnt immediately go out.

can anyone please explain why it doesnt go out immediately. Do other Vauxhalls do the same as the corsa. 1958 model.

[Hometune]

May be the float unit in the tank is sticking at low level until a jolt sends it back up.