An unpolarised light of intensity $$I$$ is passed through two polaroids kept one after the other with their planes parallel to each other. The intensity of light emerging from second polaroid is $$\frac{I}{4}$$. The angle between the pass axes of the polaroids is
In the Young's double slit experiment, the intensity of light passing through each of the two double slits is $$2 \times 10^{-2} \mathrm{~Wm}^{-2}$$. The screen-slit distance is very large in comparison with slit-slit distance. The fringe width is $$\beta$$. The distance between the central maximum and a point $$P$$ on the screen is $$x=\frac{\beta}{3}$$. Then, the total light intensity at the point is
A radioactive sample has half-life of 3 years. The time required for the activity of the sample to reduce to $$\frac{1}{5}$$th of its initial value is about
When a $$p$$-$$n$$ junction diode is in forward bias, which type of charge carriers flows in the connecting wire?