The whole question is talking about the amplitude of a wave
that's transverse and wiggling vertically.
Equilibrium to the crest . . . that's the amplitude.
Crest to trough . . . that's double the amplitude.
Trough to trough . . . How did that get in here ? Yes, that's
the wavelength, but it has nothing to do
with vertical displacement.
Frequency . . . that's how many complete waves pass a mark
on the ground every second. Doesn't belong here.
Notice that this has to be a transverse wave. If it's a longitudinal wave,
like sound or a slinky, then it may not have any displacement at all
across the direction it's moving.
It also has to be a vertically 'polarized' wave. If it's wiggling across
the direction it's traveling BUT it's wiggling side-to-side, then it has
no vertical displacement. It still has an amplitude, but the amplitude
is all horizontal.
They would most likely use statistics on the increase/decrease in population from previous decades and centuries. In addition to these statistics, they could use the birth and death rate and ultimately predict the increase within these next 30 years. They must also take climate change and other environmental factors into consideration when formulating such a bold prediction.
Answer:

Explanation:
From the question we are told that
Distance b/e antenna's 
Frequency of antenna Radiation
Distance from receiver 
Intensity of Receiver 
Distance difference of the receiver b/w antenna's 
Generally the equation for Phase difference
is mathematically given by



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Therefore phase difference f between the two radio waves produced by this path difference is given as

Answer:
charge will be equal to
Explanation:
We have given mass of the particle m = 1.45 gram = 0.00145 kg
Acceleration due to gravity 
Electric field E = 700 N/C
Electric force will be equal to
, here q is charge and E is electric field
For particle to be stationary this force must be equal to force due to gravity , that is mg force
So qE = mg

So charge will be equal to
The quantum mechanical model describes the allowed energies an electron can have. It also describes how likely it is to find the electrons in various locations around an atom's nucleus.