Adding common salt to distilled water makes it

There are two different solutions in set up $\mathrm{P}$ and $\mathrm{Q}$ as shown in figure. The bulb in the set up $\mathrm{P}$ glows more brightly as compared to that of the set up $\mathrm{Q}$. What are the possible causes for this?

$\left(\mathrm{i}\right)$ The connections of the circuit $\mathrm{Q}$ may be loose.
$\left(\mathrm{ii}\right)$ The liquid in $\mathrm{Q}$ may have small conductivity.
$\left(\mathrm{iii}\right)$ Liquid in $\mathrm{P}$ is salted water while liquid in $\mathrm{Q}$ is tap water.

Direction : Four substances were tested for their electrical conductivity. The results are shown in the table. Study the table and answer the following questions.

In substance $\mathrm{Q}$, bulb lights up but and substance is found either at cathode on at anode, why?

Direction : Four substances were tested for their electrical conductivity. The results are shown in the table. Study the table and answer the following questions.

Which solutions could be alumina and magnesium nitrate respectively?

The bumpers and door handles of motor cars, taps etc. are coated with silvery layer of chromium because
$\left(\mathrm{i}\right)$ It does not easily get corroded.
$\left(\mathrm{ii}\right)$ It forms a hard layer which does not easily get scratched.
$\left(\mathrm{iii}\right)$ It tarnishes quickly.
$\left(\mathrm{iv}\right)$ It is cheap.
Which of the following options is correctly identifies true (T) or false (F)?

The diagram shows a plotting compass placed above a copper wire when there is no current flowing in the wire. What happens to the compass needle when a large direct current flows from point $\mathrm{A}$ to point $\mathrm{B}$ ?