As per the question the wavelength of the microwave is given as 3.52 mm.
we are asked to calculate the frequency of the wave.
we know that microwave is a electromagnetic wave.
As per Clark Maxwell's electromagnetic theory ,every electromagnetic wave moves with a velocity equal to the velocity of light in vacuum and that is equal to 3×10^8 m/s.
From the equation of the wave,we know that velocity of wave is the product of frequency and wavelength.
Mathematically wave velocity 
where f is the frequency of the wave and 
is the wavelength.
As per the question 
Here 
Hence frequency of the wave 
Here Hertz [Hz] is the unit of frequency.
Each electron has a charge of
In this problem, the total charge is
Therefore, the number of electrons contained in this total charge will be given by the total charge divided by the charge of a single electron:
Use Newton's second law and the free body diagram to determine the net force and acceleration of an object. In this unit, the forces acting on the object were always directed in one dimension.
The object may have been subjected to both horizontal and vertical forces but there was no single force directed both horizontally and vertically. Moreover, when free-body diagram analysis was performed, the net force was either horizontal or vertical, never both horizontal and vertical.
Times have changed and we are ready for situations involving two-dimensional forces. In this unit, we explore the effects of forces acting at an angle to the horizontal. This makes the force act in two dimensions, horizontal and vertical. In such situations, as always in situations involving one-dimensional network forces, Newton's second law applies.
Learn more about Newton's second law here:-brainly.com/question/25545050
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Power = work / time = 8000J / 20s = 400W
I do believe all of these but core elements can be determined by spectroscopy which includes the use of electromagnetic radiation. Both the surface and core temperature can be measured using light. Surface elements can be found because the absorption lines of different elements in the spectra of the star, but I haven't heard anything about using spectral analysis for core elements.
