Can you set a resting electron into motion with a magnetic field? With an electr

Question

Can you set a resting electron into motion with a magnetic field? With an electric field? b) A charged particle is moving in a circle under the influence of a uniform, magnetic field. If an electric field that points in the same direction as the magnetic field is turned on, describe the path the charged particle will take. c) A charged particle moves in a straight line through a particular region of space. Could there be a nonzero magnetic field in this region? If so, give two possible situations. d) How could you tell whether moving electrons in a certain region of space are being deflected by an electric field or by a magnetic field (or by both)?

Explanation / Answer

(a) yes we can move an electron by using magnetic field alone, if the electron is subjected to time dependent or position dependent magnetic field i.e. magnetic field is varying in nature than it will make the electron to experience force and it can move along the direction of force.

if electric field alone is applied than due to charge on the electron it will experience force F=qE and it will move in a direction opposite to the direction of electric field in a straight line path.

(b) a charged particle can move in a circular path only If the applied magnetic field is perpendicular to the motion of the charged particle always,let charged particle is moving in a circular path in the plane of paper than magnetic field should be perpendicular to the plane of paper may be outward or inward to the plane of paper.

now if electric field is also applied along the direction of magnetic than charged particle will experience force due electric field perpendicularly outward or inward to the plane of paper i.e. in a straight line path.

thus charged particle will be under the influence of two perpendicular forces. due magnetic field it will experience centripetal force and due to electric field it will experience linear force thus while describing a circular path it moves linearly hence the path of the charged particle will be helical. it describes a helix.

(c) yes if magnetic field is nonzero than also the charged particle can move in a straight line path

   (1) if charged particle is moving along the direction of magnetic field than it will not experience any force therefore it move in a straight line path.

   (2) if both, the electric field and magnetic field applied simultaneously on the charged particle perpendicular to each other such that (vB = E) than the charged particle will experience force due to both the fields but equal in magnitude and opposite in direction therefore net force on the charged particle will be zero and it move in a straight line path.

(d) yes by looking at its path with respect to the field we can tell,

if charged particle describes a circular path than the field will be magnetic, If it move in a straight line or curved path the field will be electric and If it describes a helical path than both the fields are acting on it.

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.