current electricity Questions

As the temperature increases, the electrical resistance:

A copper wire of length $10\text{m}$ and radius $\frac{10^{-2}}{\sqrt{\pi }}\text{m}$ has electrical resistance of $10\Omega$. The current density in the wire for an electric field strength of $10\text{V/m}$ is:

Two resistors of resistances, $100\Omega$ and $200\Omega$ are connected in parallel in an electrical circuit. The ratio of thermal energy developed in $100\Omega$ to that in $200\Omega$ in a given time is:

A Wheatstone bridge is used to determine the value of unknown resistance $X$ by adjusting the variable resistance $Y$. For the most precise measurement of $X$, the resistances $P$ and $Q$: