Answer:
Draw the vector triangle (head to tail)
Let 8 be adjacent and 4 the opposite side
tan theta = 4 / 8 = .5
theta = 26.6 deg
The answer 1 is
The best-known use of radio waves is for communication; television, cellphones and radios all receive radio waves and convert them to mechanical vibrations in the speaker to create sound waves that can be heard.Electromagnetic radiation is transmitted inwaves or particles at different wavelengths and frequencies.
the answer 2 is
Radio Waves: Instant Communication
Microwaves: Data and Heat
i think the answer number 3 is
It is all about wavelength versus tunnel diameter. The wavelength of GPS is about 20cm it would happily propagate in any normal tunnel if it could get in but the earth and other structures absorb it. AM radio (600kHz - 1500kHz) cannot propagate in any normal tunnel because the wavelength is too long (500m-200m) relative to the diameter, and thus gets reflected at the entrance. FM (100MHz ~ 3m) would propagate and it does for a while but then it suffers reflections
Answer:
Work done = = 5 kJ
Explanation:
Given data:
volume of nitrogen 
Polytropic exponent n = 1.4
![\frac{T_2}{T_1} = [\frac{P_2}{P_1}]^{\frac{n-1}{n}](https://tex.z-dn.net/?f=%5Cfrac%7BT_2%7D%7BT_1%7D%20%3D%20%5B%5Cfrac%7BP_2%7D%7BP_1%7D%5D%5E%7B%5Cfrac%7Bn-1%7D%7Bn%7D)
putting all value
![\frac{T_2}{473} = [\frac{80}{150}]^{\frac{1.4-1}{1.4}](https://tex.z-dn.net/?f=%5Cfrac%7BT_2%7D%7B473%7D%20%3D%20%5B%5Cfrac%7B80%7D%7B150%7D%5D%5E%7B%5Cfrac%7B1.4-1%7D%7B1.4%7D)
polytropic process is given as
work done 
= 5 kJ
<h2>Answer: Light waves have a redshift due to the Doppler effect
</h2>
The astronomer Edwin Powell Hubble observed several celestial bodies, and when obtaining the spectra of distant galaxies he observed the spectral lines were displaced towards the red (red shift), whereas the nearby galaxies showed a spectrum displaced to the blue.
From there, Hubble deduced that the farther the galaxy is, the more redshifted it is in its spectrum. <u>The same happens with the stars and this phenomenom is known as the Doppler effect.
</u>
This phenomenon refers to the change in a wave perceived frequency (or wavelength=color) when the emitter of the waves, and the receiver (or observer in the case of light) move relative to each other. For example, as a star moves away from the Earth, its espectrum turns towards the red.
Answer:
due to the magnetic field
Explanation:
magnetic field is the same in the vacuum
