Explanation :
Absorption coefficient of a material determines how much sound is absorbed by the material.
To build a soundproof room, Heavy curtains and carpet can be used. They reduce reverberation.
Reverberation means an echoing sound which persists for some time. For example, when we bang on a huge piece of metal, we hear the reverberation even after we stop banging.
Hence, option (A) and (D) are correct.
Answer:
distance r from the uranium atom is 18.27 nm
Explanation:
given data
uranium and iron atom distance R = 44.10 nm
uranium atom = singly ionized
iron atom = doubly ionized
to find out
distance r from the uranium atom
solution
we consider here that uranium electron at distance = r
and electron between uranium and iron so here
so we can say electron and iron distance = ( 44.10 - r ) nm
and we know single ionized uranium charge q2= 1.602 ×
C
and charge on iron will be q3 = 2 × 1.602 ×
C
so charge on electron is q1 = - 1.602 ×
C
and we know F =
so now by equilibrium
Fu = Fi
=
put here k =
and find r
=

r = 18.27 nm
distance r from the uranium atom is 18.27 nm
I’m pretty sure
Part 1; C
Part 2; C
Not 100% sure tho :)
Answer: 0.4 km/h
100 m = 0.1 km
15min./60min. = 0.25 hr
so, divide the total distance (100 m) by the total time (15 min)
0.1 km/0.25 hr = 0.4