Which of the following graphs represents an ohmic resistor?

$E$ is the electric field inside a conductor whose material has conductivity $\sigma$ and resistivity $\rho$. The current density inside the conductor is $J$. The correct form of Ohm's law is

Which of the following statements is correct?

The $V-i$ graph for a conductor makes an angle $\theta$ with the $V$-axis. Here $V$ denotes the voltage and $i$ denotes the current. The resistance of the conductor is given by:

The charge $q$ (in coulomb) passing through a $10 \, \Omega$ resistor as a function of time $t$ (in second) is given by $q = 3t^2 - 2t + 6$. The potential difference across the ends of the resistor at time $t = 5 \, s$ is: (in $V$)

For a metallic wire,the ratio $V/i$ ($V =$ the applied potential difference,$i =$ current flowing) is