What is meant by resistance?

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.

The resistivity of all pure metals increases with an increase in temperature.

An electric refrigerator rated $400 \ W$ operates $8 \ h$ per day. What is the cost of the energy to operate it for $30$ days at ₹ $3.00$ per $kWh$?

$(a)$ $(i)$ What is meant by saying that the potential difference between two points is $1 \, V$? $(ii)$ How much energy is given to $5 \, C$ of charge passing through a $12 \, V$ battery? $(b)$ Describe an activity with a necessary electric circuit to study the factors on which the resistance of a conducting wire depends.

$1 \; kWh = \ldots \ldots \; \text{joules}$