Consider the following statements
$1$. Ohm's law is applicable to all conductors.
$2$. The resistance of a pure metallic wire increases with increasing temperature.
$3$. The equivalent resistance of a set of resistors joined in parallel is less than the value of smallest resistor in the set,
Which of the following statement is/are correct?

A parallel plate air condenser is charged by connecting it to a battery. The battery is disconnected and then a sheet of glass of dielectric constant $8$ is inserted between the plates. In this context, which of the following would be true ?

$1$. Potential difference between the plates is reduced by a factor of eight.
$2$. Potential difference between the plates is increased by a factor of eight.
$3$. Electric field between the plates is reduced by a factor of eight.

Select the correct answer from the code given below

Which one among the following is the true representation of 
$\left(\mathrm{i}\right)$ variable $DC$ potential

$\left(\mathrm{ii}\right)$ rheostat and

$\left(\mathrm{iii}\right)$ $AC$ ammeter, respectively?

Consider the following circuit:

The current flowing through each of the resistors connected in the above circuit is: