Answer:
Part a)


Part b)

Explanation:
Part a)
Constant speed by which the student will run is given as

now after some time if student is going to overtake the position of bus
so here the final positions will be same
so we have




so it is

So student will run the total distance



Part b)
Speed of bus when student reach the bus is given as



D) Partial charge cannot be removed, because charge is a discrete quantity that may exist only at certain values
Explanation:
The electric charge of an object is a property of the object that is related to the ability of the object to experience/exert an electric force: if the object is electrically charge, then it is attracted or repelled by other electrically charged object.
The electric charge of an object depends on the amount of charged particles it has on it. In particular, the fundamental particles that carry electric charge are:
- Protons: they carry electric charge of +e
- Electrons: they carry electric charge of -e
Where "e" is the fundamental charge (
). Therefore, one proton carry a charge of +e and one electron carry a charge of -e.
An electron is a fundamental particle: this means that it cannot be divided into smaller particles. This also means that it is not possible to remove part of the charge of the electron: in fact, it is said that electric charge exists only as discrete values, being a multiple of
. Therefore, the correct statement is
D) Partial charge cannot be removed, because charge is a discrete quantity that may exist only at certain values
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To develop this problem it is necessary to apply the Rayleigh Criterion (Angular resolution)criterion. This conceptos describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution. By definition is defined as:

Where,
= Wavelength
d = Width of the slit
= Angular resolution
Through the arc length we can find the radius, which would be given according to the length and angle previously described.
The radius of the beam on the moon is

Relacing 


Replacing with our values we have that,


Therefore the diameter of the beam on the moon is



Hence, the diameter of the beam when it reaches the moon is 7361.82m
Answer:
A police car with its siren on is driving towards you, and you perceive the pitch of the siren to increase.
Explanation:
In Physics, Doppler effect can be defined as the change in frequency of a wave with respect to an observer in motion and moving relative to the source of the wave.
Simply stated, Doppler effect is the change in wave frequency as a result of the relative motion existing between a wave source and its observer.
The term "Doppler effect" was named after an Austrian mathematician and physicist known as Christian Johann Doppler while studying the starlight in relation to the movement of stars.
<em>The phenomenon of Doppler effects is generally applicable to both sound and light. </em>
An example of the Doppler effect is a police car with its siren on is driving towards you, and you perceive the pitch of the siren to increase. This is so because when a sound object moves towards you, its sound waves frequency increases, thereby causing a higher pitch. However, if the sound object is moving away from the observer, it's sound waves frequency decreases and thus resulting in a lower pitch.
<em>Other fields were the Doppler effects are applied are; astronomy, flow management, vibration measurement, radars, satellite communications etc. </em>