Insert an irrational number between the following :

(i) $\dfrac{1}{3}$ and $\dfrac{1}{2}$

(ii) $-\dfrac{2}{5}$ and $\dfrac{1}{2}$

(iii) 0 and 0.1

Insert two irrational number between 2 and 3.

Find a rational number between $\sqrt{2}$ and $\sqrt{3}$.

Find two rational numbers between $2\sqrt{3}$ and $\sqrt{15}$.