Which of the following is the best as shaving mirror?

A refrigerator uses 150W. If it is kept on for 336 hours non-stop, what is the energy consumed in KWh?

What is the inductance reactance of a coil of 7H when connected to a 50Hz a.c circuit?

If a charge ion goes through a combined electric field E and magnetic field B, the resultant emergent velocity of the ion is 

In electrolysis, when same quantity of electricity is passed through different electrolytes, mass of substances deposited is proportional to