Molality of an aqueous solution of urea is $$4.44 \mathrm{~m}$$. Mole fraction of urea in solution is $$x \times 10^{-3}$$, Value of $$x$$ is ________. (Integer answer)

Wavenumber for a radiation having 5800 $$\mathop A\limits^o $$ wavelength is $$x \times 10 \mathrm{~cm}^{-1}$$ The value of $$x$$ is ________. (Integer answer)

Number of molecules having bond order 2 from the following molecules is _________.

$$\mathrm{C}_2, \mathrm{O}_2, \mathrm{Be}_2, \mathrm{Li}_2, \mathrm{Ne}_2, \mathrm{~N}_2, \mathrm{He}_2$$

Let $$y=y(x)$$ be the solution curve of the differential equation $$\sec y \frac{\mathrm{d} y}{\mathrm{~d} x}+2 x \sin y=x^3 \cos y, y(1)=0$$. Then $$y(\sqrt{3})$$ is equal to: