Which particles are responsible for the flow of current in conductors?

Give two practical applications of the heating effect of current.

The applied potential difference across a given resistor is altered so that the heat produced per second increases by a factor of $16.$ By what factor does the applied potential difference change?

What is the power of a bulb rated at $2.5 \, V$ and $500 \, mA$ (in $, W$)?

Silicon is $......$

What are the essential requirements of a heater filament?