Answer:
a.proton, proton
hope this helped :) have a goodday
To solve this problem we will use the Ampere-Maxwell law, which describes the magnetic fields that result from a transmitter wire or loop in electromagnetic surveys. According to Ampere-Maxwell law:

Where,
B= Magnetic Field
l = length
= Vacuum permeability
= Vacuum permittivity
Since the change in length (dl) by which the magnetic field moves is equivalent to the perimeter of the circumference and that the electric flow is the rate of change of the electric field by the area, we have to

Recall that the speed of light is equivalent to

Then replacing,


Our values are given as




Replacing we have,



Therefore the magnetic field around this circular area is 
Answer: Wave speed may equal frequency*wavelength. Yet doubling the frequency only halves the wavelength; wave speed remains the same. To change the wave speed, the medium would have to be changed. 24. What are some simple steps I can take to protect my privacy online? Many people ... So if you double the frequency and keep the speed constant, the wavelength halves to give the same speed with the doubled frequency. 3.8k views ... The period of a note is 0.3 seconds and the speed of sound in air is 340 m/s. So if you double the frequency and keep the speed constant, the wavelength halves to give the same speed with the doubled frequency. What is the period of a wave if the wavelength is 100m and the speed is 200 m/s? ... If you move towards a light source, the wavelength decreases.
Explanation:
The answer is 2 because a and b are slowing it down by condensing it and then freezing it so its not one, b and c are opposites because b slows it down whereas c speeds it up so its not 3, and number 4 is the same explanation for number 3
hope you pass :)