$$ \text { If } \mathrm{AB} \text { is incident plane wave front then refracted wave front in }\left(\mathrm{n}_2>\mathrm{n}_1\right) $$

Three polaroid sheets are co-axially placed as indicated in the diagram. Pass axes of the polaroids 2 and 3 make $30^{\circ}$ and $90^{\circ}$ with pass axis of polaroid sheet 1 . If $I_0$ is the intensity of the incident unpolarised light entering sheet 1 , the intensity of the emergent light through sheet 3 is

In Young's double slit experiment, an electron beam is used to produce interference fringes of width $\beta_1$. Now the electron beam is replaced by a beam of protons with the same experimental set-up and same speed. The fringe width obtained is $\beta_2$. The correct relation between $\beta_1$ and $\beta_2$ is