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
R=U^2/P=120*120/40=360 ohm
P2=U2^2/R=132*132/360=48.4 w
power increase ratio (48.4-40)/40=21%
Answer:
1) true
2) false
3) false
4) true
5) true
6) true
7) true
8) false
9) true
10) false
i think these are correct if im wrong on a few im sorry. Hope this helps at least a bit. And if i do get some wrong you know just to pick the opposite answer.
Answer:
1–
Explanation:
The fluorine is the element with biggest electronegativity in the periodic table, so it usually always take an electron and gets charge 1–