Electron Motion in a Long Solenoid

In summary, the conversation discusses a long solenoid with 100 turns/cm and carrying a current i, where an electron moves in a circle with a radius of 0.022 cm and a speed of 0.048c. The equations used to solve for the current include f = m*v^2/r = q*v*B, B of a solenoid = u*n*I, and I = mv/(r*q*u*n). There was a discrepancy in the final answer, which was resolved by using the correct value for the mass of the particle involved.
  • #1
jehan60188
203
1

Homework Statement



A long solenoid has 100 turns/cm and carries a current i. An electron moves within the solenoid in a circle of radius 0.022 cm perpendicular to the axis of the solenoid. The speed of the electron is 0.048c (c is the speed of light).

Homework Equations



f = m*v^2/r = q*v*B
B of a solenoid = u*n*I
where n = number of turns per meter
u = 4*pi*10^7


The Attempt at a Solution



so B = mv/(r*q) = u*n*I
I = mv/(r*q*u*n)
I = 5436.9 is not correct
 
Physics news on Phys.org
  • #2
your working looks fine to me... But I got a different value for the current when I plugged the numbers in. Maybe that's where the problem is.
 
  • #3
I was using the mass of a proton instead of an electron. replugged the numbers, and it works now!
thanks!
 

Related to Electron Motion in a Long Solenoid

1. How does an electron move in a long solenoid?

Electrons move in a long solenoid due to the presence of a magnetic field. When a current is passed through the solenoid, it creates a magnetic field that exerts a force on the electrons, causing them to move in a circular path around the solenoid.

2. What is the direction of electron motion in a long solenoid?

The direction of electron motion in a long solenoid is perpendicular to both the direction of the current and the direction of the magnetic field. This is known as the right-hand rule, where the thumb represents the direction of the current, the fingers represent the direction of the magnetic field, and the palm represents the direction of the electron motion.

3. Does the speed of the electron change in a long solenoid?

Yes, the speed of the electron changes in a long solenoid due to the magnetic force exerted on it. As the electron moves in a circular path, it experiences a centripetal force that keeps it in motion. This results in a constant change in velocity, but the speed remains the same.

4. How does the number of turns in a solenoid affect electron motion?

The number of turns in a solenoid affects the strength of the magnetic field. As the number of turns increases, the magnetic field also increases, resulting in a stronger force on the electrons. This causes the electrons to move in a tighter, faster circular path.

5. What is the relationship between the strength of the magnetic field and the radius of electron motion in a long solenoid?

The strength of the magnetic field is directly proportional to the radius of electron motion in a long solenoid. This means that as the magnetic field increases, the radius of the electron's circular path also increases. This relationship is described by the equation F=qvB, where F is the magnetic force, q is the charge of the electron, v is the velocity, and B is the magnetic field strength.

Similar threads

  • Introductory Physics Homework Help
Replies
3
Views
339
  • Introductory Physics Homework Help
Replies
7
Views
310
  • Introductory Physics Homework Help
Replies
5
Views
888
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
900
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
3K
  • Introductory Physics Homework Help
Replies
9
Views
5K
  • Introductory Physics Homework Help
Replies
3
Views
2K
Back
Top