A positively charged particle travels horizontally northward and enters a region where a field may exist. This region may contain only a magnetic field, only an electric field, or both a magnetic field and an electric field. When the particle enters the region, the particle does not speed up or slow down, but it does deflect in the downward direction. Which of the following statements is correct about the field or fields within the region and provides correct reasoning? a. Only a southward electric field is present, because then an electric force will bend the particle parabolically.
b. Only a southward electric field is present, because then an electric force will cause the particle to undergo circular motion.
с. Only a southward magnetic field is present, because then a magnetic force will cause the particle to undergo circular motion.
d. Only a southward magnetic field is present, because then a magnetic force will bend the particle parabolically.
e. A southward electric field and an eastward magnetic field are present, because then the forces can cause the particle to deflect without accelerating.