Answer:
1. Hot air is less dense and has moved upward allowing cool air to move downward which is less dens
(Convection current)
2. The ceiling has transferred heat to him by radiation.
Explanation:
During the day when air is heated as a result of the ceiling transferring heat to it, it becomes less dens and it gains energy, which make it lighter in weight than cooler air, this hot air moves upward allowing cooler air to move downward.
Statement :- We assume the orthagonal sequence
in Hilbert space, now
, the Fourier coefficients are given by:

Then Bessel's inequality give us:

Proof :- We assume the following equation is true

So that,
is projection of
onto the surface by the first
of the
. For any event, 
Now, by Pythagoras theorem:


Now, we can deduce that from the above equation that;

For
, we have

Hence, Proved
Answer:
L= 0.059 mH
Explanation:
Given that
R = 855 Ω and C = 6.25 μF
V= 84 V
Frequency
ω = 51900 1/s
We know that

L=Inductance
C=Capacitance
ω =angular Frequency
ω² L C =1
(51900)² x L x 6.25 x 10⁻⁶ = 1
L= 5.99 x 10⁻⁵ H
L= 0.059 mH
Hi alexander it is very true air pollution is only caused by human activity
You are correct!
Happy to assist you!