The magnitude of the source charge is 3 μC which generates 4286 N/C of the electric field. Option B is correct.
What does Gauss Law state?
It states that the electric flux across any closed surface is directly proportional to the net electric charge enclosed by the surface.

Where,
 =	electric force = 4286 N/C
 =	electric force = 4286 N/C 
 =	Coulomb constant =
 =	Coulomb constant = 
 =	charges = ?
     =	charges = ?
 =	distance of separation = 2.5 m
 =	distance of separation = 2.5 m
Put the values in the formula,

Therefore, the magnitude of the source charge is 3 μC.
Learn more about Gauss's law:
brainly.com/question/1249602
 
        
             
        
        
        
Answer:
The height is 3.1m
Explanation:
Here we have a conservation of energy problem, we have a conversion form eslastic potencial  energy to gravitational potencial energy, so:

then we have only gravitational potencial energy when the ball is at its maximun height.

because all the energy was transformed Eg=Ee

searching the web, the mass of a ping pong ball is 2.7 gr in average. so:

 
        
             
        
        
        
Answer:
A vacuum
Explanation:
Sound waves are examples of mechanical waves. Mechanical waves are waves which are transmitted through the vibrations of the particles in a medium.
For example, sound waves in air consist of oscillations of the air particles, which vibrate back and forth (longitudinal wave) along the direction of propagation of the wave itself.
Given this definition of mechanical wave, we see that such a wave cannot propagate if there is no medium, because there are no particles that would oscillate. Therefore, among the choices given, the following one:
a vacuum
represent the only situation in which a sound wave cannot propagate through: in fact, there are no particles in a vacuum, so the oscillations cannot occur. In all other cases, instead, sound waves can propagate.