Different types of fronts produce different patterns of weather. When a cold, dense air mass pushes warmer air, it produces a cold front. A cold front can turn a heat wave into normal summer weather or turn cold winter air into very cold weather. Cold fronts often produce tall cumulonimbus clouds.
If you look at the picture you will see how, but the answer is 0.5 Hz.
To put it another way, stationary states are the same as time-independent currents. Moreover, such currents are not sources of radiation, according to Maxwell's theory. The atom will remain in its natural state and will not collapse due to a shortage of energy.
DB = 10 log (I/Io)
Where, Io is the reference intensity which is the minimum intensity that human can hear.
That is; Io = 10^-12
Therefore;
dB = 10 log (0.000127/10^-12) =80.79
= 81 dB
Therefore; the correct answer is 81 dB