Assertion: The colour of a green flower seen through red glass appears to be dark.
Reason: Red glass transmits only red light.

The solar spectrum during a complete solar eclipse is

Evidence for the wave nature of light cannot be obtained from

Column $I$ shows four situations of standard Young's double slit arrangement with the screen placed far away from the slits $S_1$ and $S_2$. In each of these cases $S_1 P_0 = S_2 P_0$,$S_1 P_1 - S_2 P_1 = \lambda / 4$ and $S_1 P_2 - S_2 P_2 = \lambda / 3$,where $\lambda$ is the wavelength of the light used. In the cases $B, C$ and $D$,a transparent sheet of refractive index $\mu$ and thickness $t$ is pasted on slit $S_2$. The thicknesses of the sheets are different in different cases. The phase difference between the light waves reaching a point $P$ on the screen from the two slits is denoted by $\delta(P)$ and the intensity by $I(P)$. Match each situation given in Column $I$ with the statement$(s)$ in Column $II$ valid for that situation.

Column $I$	Column $II$
$(A)$ No sheet	$(p)$ $\delta(P_0) = 0$
$(B)$ $(\mu-1)t = \lambda / 4$	$(q)$ $\delta(P_1) = 0$
$(C)$ $(\mu-1)t = \lambda / 2$	$(r)$ $I(P_1) = 0$
$(D)$ $(\mu-1)t = 3\lambda / 4$	$(s)$ $I(P_0) > I(P_1)$
	$(t)$ $I(P_2) > I(P_1)$

Compare and contrast the interference and diffraction.

What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room,its intensity essentially remains constant. What geometrical characteristic of $LASER$ beam is responsible for the constant intensity which is missing in the case of light from the bulb?