[101] Magnetic field strength in fN

[WPCareyDevil]

[SOLVED] [101] Magnetic field strength in fN

Homework Statement

You have arranged that the magnetic field in a particular region of space is due North with a value of 0.01 T. An electron enters the field traveling to the West with a speed of 0.05 of the speed of light. As a result, the electron experiences a magnetic force which is upwards.

(a) What is the strength of this magnetic force, in fN? (NOTE: The "f" stands for "femto", which is 10-15.)



(b) What is the amount of the resulting acceleration of the electron? (NOTE: Get the mass of an electron from the inside back cover of your textbook.)

Homework Equations

B=.01T
B=2ki/c^2r

F=ma

The Attempt at a Solution

B will be very strait forward once I have answered a. I already know the strength of the magnetic force (B) in Tesla. So, it seems that I just need to convert tesla to femto Newtons. Can someone lead me in the right direction?

I am not very familiar with this concept.

Thank you SO much!

 

[Nabeshin]

Tesla is a measure of magnetic field strength, not force. For a charged particle moving through a magnetic field, the force it feels is given by F=qVxB where q is the charge on the particle, V is its velocity, and B is the magnetic field. The x indicates cross product. Again, the Tesla value is a FIELD strength, not a force.

 

[Moetasim]

I can provide some guidance on how to approach this problem. First, it's important to understand the units involved. The magnetic field strength is given in Tesla (T), which is the SI unit for magnetic field. The femto prefix (f) represents 10^-15, so fN stands for femto Newtons, which is a unit of force.

To solve for the magnetic force (F), we can use the equation F=qvB, where q is the charge of the electron, v is its velocity, and B is the magnetic field strength. Since the electron has a negative charge, the direction of the force will be perpendicular to both its velocity and the magnetic field, and in this case it will be upwards.

To convert from Tesla to femto Newtons, we can use the conversion 1 T = 10^15 fN. So, the magnetic force in fN can be calculated as:

F = qvB = (1.6x10^-19 C)(0.05c)(0.01 T) = 8x10^-25 fN

For part (b), we can use the equation F=ma to solve for the acceleration (a). Since we already know the force (F) and the mass of an electron (m), we can rearrange the equation to solve for a:

a = F/m = (8x10^-25 fN)/(9.11x10^-31 kg) = 8.78x10^5 m/s^2

I hope this helps guide you in the right direction. Remember to always pay attention to units and use the appropriate equations to solve for the desired quantities.