Calculating the magnitude of the force on an electron

[jaa72]

Homework Statement

an electron travels at a speed of 2.0X10^4 m/s threw a uniform magnetic field whose magnitude is 1.2x10^4 T. what is the magitude of of the force on the electron if its velocity vector and magnetic vector are
a)parralel
b)45degrees
c)parralel

Homework Equations

Fmax=QVB
F=QVSintheta

The Attempt at a Solution

for a i got .0012
b i got 16.47N
c i got 0
i think i am using the wrong equations

 

[rock.freak667]

well using the right hand rule, which says that the current,force and magnetic field are at 90 degrees to each other, you'd see that if the velocity direction is parallel to the magnetic field you have no force.

Use th equation F=BQvsin$\theta$ to get the force for part b

 

[nlightner]

Hi there,

I would approach this problem by first understanding the basic principles involved. The force on a charged particle moving through a magnetic field is given by the equation F = qvB, where q is the charge of the particle, v is its velocity, and B is the magnetic field strength. In this case, we are dealing with an electron, which has a charge of -1.6x10^-19 C.

Now, let's look at the different scenarios given in the problem:

a) In this case, the velocity vector and magnetic vector are parallel, meaning they are pointing in the same direction. This means that the angle between them is 0 degrees, and we can use the first equation to calculate the force. Plugging in the values given, we get:

F = (1.6x10^-19 C)(2.0x10^4 m/s)(1.2x10^4 T) = 3.84x10^-11 N

b) In this case, the velocity vector and magnetic vector are at an angle of 45 degrees. This means that the force will be less than in the previous case, since only the component of the velocity vector that is perpendicular to the magnetic field will experience a force. We can use the second equation to calculate this component:

F = (1.6x10^-19 C)(2.0x10^4 m/s)sin(45 degrees)(1.2x10^4 T) = 2.71x10^-11 N

c) In this case, the velocity vector and magnetic vector are perpendicular, meaning they are at an angle of 90 degrees. This means that the force will be 0, since the sine of 90 degrees is 1. This is because the force on a charged particle moving through a magnetic field is always perpendicular to both the velocity and magnetic field vectors.

So, to summarize, the magnitude of the force on the electron will be 3.84x10^-11 N when the velocity and magnetic vectors are parallel, 2.71x10^-11 N when they are at an angle of 45 degrees, and 0 when they are perpendicular. I hope this helps!