It transfers and changes into different types of energy, this is why the ground feels hot when something moves fast over it.
Accelerating voltage<span> is the difference in potential between the filament and the anode,and it can be varied between 5 KeV and 30 KeV on the S-500 and between 2 KeV and 30 KeV on the S-450. As the </span>voltage<span> is increased, the electrons travel with higher velocity and are more energetic.</span>
If one of the variables is changed, that tells nothing about what happens to the other one, or IF anything happens, or when, or how long it lasts. Because they are UN-RELATED. You just said so yourself.
None of the choices says this.
b is the answer there you go if you need the answer