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Date Posted: 7/24/2008 3:31:45 PM  Status: Live
life saver for the correct answer ..
Course Textbook Chapter Problem
Calculus Based Physics University Physics with Modern Physics (12th) by Young, Freedman 27 6
Question Details:
I will rate , PROMISA
 
 
An electron moves at 3.00×106 m/s through a region in which there is a magnetic field of unspecified direction and magnitude 8.00×10−2 T.
 
Part A
What is the largest possible magnitude of the acceleration of the electron due to the magnetic field?
  a  =
  {\rm m/s^2}
submitgive up

Part B
What is the smallest possible magnitude of the acceleration of the electron due to the magnetic field?
  a  =
  {\rm m/s^2}
submitgive up

Part C
If the actual acceleration of the electron is \frac{1}{4} of the largest magnitude in part (a), what is the angle between the electron velocity and the magnetic field?
  \phi  =
  ^\circ
submitgive up

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Karma Points: 738
Date Posted: 7/24/2008 4:40:59 PM  Status: Live
Asker's Rating: Lifesaver   
Response:
Part A:
The largest possible acceleration occurs when the magnetic field is perpendicular to the direction the electron is moving.
Using the equation
F=qvB (for v is perpendicular to B)
and F=ma
We can solve for acceleration
a = qvB/m
 
Given that
q = 1.6 * 10^-19 C
m = 9.11*10^-31 kg
v=3*10^6 m/s
B= 8 * 10^-2 T
 
a = (1.6 * 10^-19)(3*10^6)(8 * 10^-2) / (9.11*10^-31) = 4.22*10^16 m/s^2
(Sorry if the math is wrong, I don't have a good calculator on hand)
 
Part B
The smallest acceleration occurs when the magnetic field is parallel to the velocity, in which case no force is exerted on the electron by the field. Thus the minimum acceleration is 0 m/s
 
Part C
Divide the acceleration from part A by 4, and we get 1.05 * 10^16 m/s^2
Now we backtrack using F=qvB and F=ma
Since time, the equation is altered to F=qvBsinθ , because the velocity is no longer perpendicular to the field.
 
Solving for θ
sinθ = ma/qvB
sinθ = (9.11*10^-31)(1.05 * 10^16) / (1.6*10^-19)(3*10^6)(8*10^-2)
sinθ = 0.249
θ= sin-1 (0.249)
Once again, I don't have the calculator to solve this, but that should give you the answer.
Girl.physics's Comment:
Thaaaaaaaaanks

Physics doesn't suck; it just blows.



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