Once a current has been established in a superconducting material, how much energy is needed to keep it going?
a. None.
b. Energy must be continuously provided as the same rate that was used to establish the current in the first place.
c. Energy must continue to be provided at a lower rate than initially.
d. Superconductors remove energy from the environment to maintain the current.
e. The power needed to maintain the current is half that to establish it initially.
a
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