An organic compound undergoes first order decomposition. The time taken for decomposition to $\left(\frac{1}{8}\right)^{\text {th }}$ and $\left(\frac{1}{10}\right)^{\text {th }}$ of its initial concentration are $\mathrm{t}_{1 / 8}$ and $\mathrm{t}_{1 / 10}$ respectively.

What is the value of $\frac{\mathrm{t}_{1 / 8}}{\mathrm{t}_{1 / 10}} \times 10$ ?

$$ (\log 2=0.3) $$

In the given pentapeptide, find out an essential amino acid $(\mathrm{Y})$ and the sequence present in the pentapeptide :

$$ \text { Choose the correct answer from the options given below : } $$

At $\mathrm{T}(\mathrm{K}), 2$ moles of liquid A and 3 moles of liquid B are mixed. The vapour pressure of ideal solution formed is 320 mm Hg . At this stage, one mole of A and one mole of B are added to the solution. The vapour pressure is now measured as 328.6 mm Hg . The vapour pressure (in mm Hg ) of A and B are respectively:

The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series.

( $\mathrm{R}=$ Rydberg constant)