What does a “fixed amount of fuel” mean?

A "fixed price" energy tariff means that your unit price for gas and electricity will not change for the duration of the plan. A variable rate means your energy price can vary during the plan. If you have a fixed price plan and your supplier announces a price rise, your rates will not change.

Explanation: Google

A "fixed price" energy tariff means that your unit price for gas and electricity will not change for the duration of the plan. A variable rate means your energy price can vary during the plan

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A very large amount

Explanation:

r = ρ x length / area  

ρ = r x area / length  

ρ is in ohm-meters  

in basic units, it is m³kg/s³a²  

i think this is it.