From which plant is palm oil obtained?

$A$ light wave has a frequency of $4 \times 10^{14} \text{ Hz}$ and a wavelength of $5 \times 10^{-7} \text{ m}$ in a medium. The refractive index of the medium is

Aluminium chloride exists as a dimer,$Al_2Cl_6$,in the solid state as well as in solutions of non-polar solvents such as benzene. When dissolved in water,it gives:

The chemical reaction that involves the roasting process is

Two beams of light having intensities $I$ and $4I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\pi / 2$ at point $A$ and $\pi$ at point $B$. Then the difference between the resultant intensities at $A$ and $B$ is (in $I$)

The path difference between the two waves $y_1 = a_1 \sin \left( \omega t - \frac{2\pi x}{\lambda} \right)$ and $y_2 = a_2 \cos \left( \omega t - \frac{2\pi x}{\lambda} + \phi \right)$ is