The formula for an electric current is $.....$

In a Voltaic cell,what is the positive electrode (cathode) made of?

$(a)$ What is meant by saying that the potential difference between two points is $1$ volt?
$(b)$ Why does the connecting cord of an electrical heater not glow while the heating element does?
$(c)$ Electrical resistivities of some substances at $20^{\circ}C$ are given below:

Silver	$1.60 \times 10^{-8} \, \Omega m$
Copper	$1.62 \times 10^{-8} \, \Omega m$
Tungsten	$5.2 \times 10^{-8} \, \Omega m$
Iron	$10.0 \times 10^{-8} \, \Omega m$
Mercury	$94.0 \times 10^{-8} \, \Omega m$
Nichrome	$100 \times 10^{-6} \, \Omega m$

Answer the following questions in relation to them:
$(i)$ Among silver and copper, which one is a better conductor? Why?
$(ii)$ Which material would you advise to use in electrical heating devices? Why?

Which instrument is used to measure electric current?

What happens to the resistance of a conductor when its temperature is increased?

The rating of an electric heater is $1100 \ W, 220 \ V$. Calculate its resistance when it operates at $220 \ V$. Also,calculate the energy consumed in $kWh$ in the month of November,if the heater is used daily for four hours at the rated voltage.