The answer to this question is "LIES BELOW THE SURFACE" happens or occurs. When one of the main differences between the two which is the Intaglio and the other one is the relief printing processes is that with the Intaglio the ink LIES BELOW the surface of the printing plate.
Answer:
Since 2 pi = 360 deg and pi equals 180 deg, 30 deg = pi / 6.
S = theta * R = pi / 6 * 3 cm = 1.57 cm
The answer to this is D. Green.
Sound level at distance of 15 m is given as 20 dB
so intensity at this distance is given as



now if we move closer to some some distance the sound level is now 50 dB
now the intensity is given as



now we know that



so now the distance from friend must be 47 cm
I think it might be a or d i hope i have helped :)