Two conducting wires of the same material,equal length,and equal diameter are connected in series. How does the heat produced by the combination of resistance change?

What is the maximum resistance which can be made using five resistors each of $1/5 \ \Omega$ (in $Omega$)?

$B_{1}$,$B_{2}$ and $B_{3}$ are three identical bulbs connected as shown in the figure. When all the three bulbs glow,a current of $3 \, A$ is recorded by the ammeter $A$.
$(i)$ What happens to the glow of the other two bulbs when the bulb $B_{1}$ gets fused?
$(ii)$ What happens to the reading of $A_{1}$,$A_{2}$,$A_{3}$ and $A$ when the bulb $B_{2}$ gets fused?

If the cross-sectional area of a conducting wire is doubled,what will be the effect on its resistance?

Which of the following is the symbol for a resistor?

Explain the terms potential and potential difference. Give their $SI$ units.