Answer:
6.5 × 10¹⁵/ cm³
Explanation:
Thinking process:
The relation 
With the expression Ef - Ei = 0.36 × 1.6 × 10⁻¹⁹
and ni = 1.5 × 10¹⁰
Temperature, T = 300 K
K = 1.38 × 10⁻²³
This generates N₀ = 1.654 × 10¹⁶ per cube
Now, there are 10¹⁶ per cubic centimeter
Hence, 
C. seems like the best answer. i may be wrong so don’t quote me on that
Answer:
not sure if this helps but
Answer:
Racking is the term used for when buildings tilt as their structural components are forced out of plumb. This is most commonly caused by wind forces exerting horizontal pressure, but it can also be caused by seismic stress, thermal expansion or contraction, and so on.
Explanation:
