Which from following polymers is classified fibres depending on inter molecular forces?

Calculate the frequency if wavelength is $$750 \mathrm{~nm}$$.

Calculate the edge length of bcc unit cell if radius of metal atom is $$227 \mathrm{~pm}$$.

Identify the compound '$$\mathrm{A}$$' in the following sequence of reactions.

$$\text { A } \xrightarrow[\text { Dryether }]{\mathrm{C}_2 \mathrm{H}_3 \mathrm{MgBr}} \mathrm{B} \xrightarrow{\mathrm{H}_3 \mathrm{O}^{+}} \text {3-Methylpentan-3-0l }$$