What is the unit of $Watt-second$?

What is meant by "electrical resistance" of a conductor? State how the resistance of a conductor is affected when $(i)$ a low current passes through it for a short duration; $(ii)$ a heavy current passes through it for about $30$ seconds.

An electric iron consumes energy at a rate of $840\, W$ when heating is at the maximum rate and $360\, W$ when the heating is at the minimum. The voltage is $220\, V$. What are the current and the resistance in each case?

Why is very less heat generated in long electric cables than in filaments of electric bulbs?

Which type of metal or alloy cannot be used to prepare a fuse wire?

From the listed electrical devices,which releases heat energy that is not appreciated?