Which of the following materials has the highest number of free electrons?

What is the resistance of an ideal ammeter?

Define $1$ volt.

$(a)$ Why is the series arrangement not used for domestic circuits?
$(b)$ Why is tungsten used almost exclusively for the filament of electric lamps?
$(c)$ Why are the conductors of electric heating devices,such as bread toasters and electric irons,made of an alloy rather than a pure metal?
$(d)$ Why are copper and aluminium wires usually employed for electricity transmission?
$(e)$ Why does the cord of an electric heater not glow while the heating element does?

$1\, mA = \dots A$

Give a single word for $\frac{1 \text{ joule}}{1 \text{ coulomb}}$.