Superconductors Have Been Discussed as a Means for Electrical Energy

Multiple Choice

Superconductors have been discussed as a means for electrical energy storage.Because they are resistanceless,a current once started in a loop would continue without loss.If a current of 1.0 × 10⁴ A were started in a huge toroidal coil of radius 1.0 km and inductance 50 H,how much electrical energy (in kWh) could be stored?

A) 300 kWh
B) 480 kWh
C) 690 kWh
D) 840 kWh