Question

In the figure, a ray of light is incident on a transparent liquid contained in a thin glass box at an angle of 45° with its one face. The emergent ray passes along the face AB. Find the refractive index of the liquid.

The displacement of two light waves, each of amplitude 'a' and frequency ω, emanating from two coherent sources of light, are given by y₁ = a cos ωt and y₂ = a cos (ωt + φ). φ is the phase difference between the two waves. These light waves superpose at a point. Obtain the expression for the resultant intensity at that point.

In Young's double slit experiment, find the ratio of intensities at two points on a screen when waves emanating from two slits reaching these points have path differences (i) λ/6 and (ii) λ/12.

Assertion (A) : The temperature coefficient of resistance is positive for metals and negative for p-type semiconductors. Reason (R) : The charge carriers in metals are negatively charged, whereas the majority charge carriers in p-type semiconductors are positively charged.