Question

1.In a superconductor (and sometimes on Star Trek) it is said “Resistance is Futile”. Interpret and apply this in terms of electrical properties of materials.

2.What is a kilowatt-hour? Why are they used instead of Joules?

3.When are Kirchhoff’s rules necessary to analyze a circuit?

Answer 1

1) In the case of supercoductor if we reduce the temperature and reaches near transition temperature there is sudden decrease in temperature. The resistance drop to about of its value above transition value. This much small value can be neglected. Hence we can say resistance is futile.

2) Kilowatt hour is a unit of enrgy and this is the energy consumed for 1 kW of power operated for 1 hour. E= Power* time= 1kW*3600s=3600 J

It is is commonly used in electricity billing since it easy dealing with the numerical values. Normal hose hold energy conception can about few hundreds of kilowatt hour.