Question

An electron is accelerated from rest through a potential difference of 3750 V. It enters a region where B = 4.0 x 10^-3 T perpendicular to its velocity. Calculate the radius of the path it will follow.

Would I use the equation: mv^2/r = qvB; where r = mv/qB ?

Answer 1

yes...be careful..here v is the velocity of the electron..not the potential difference..!

Answer 2

hmm...ok... so m = mass of the electron, v = velocity of electron, q = charge of electron and B = magnetic force? is that right?

Answer 3

and all are given besides V, so, do I need to find V first in order to use the first equation?

Answer 4

hm

Answer 5

yep. im kinda stumped here ha.

Answer 6

the electron is accelerated from rest through a potential difference V (say)
then the kinetic energy of the electron=work done
1/2mv^2=qV.....[v=velocity of electron , V=potential difference]
mv^2=2qV
(mv)^2=2qmV
mv=(2qmV)^1/2
now ur eqn reduced to..r={(2qmV)^1/2}/qB

Answer 7

hmm... ok I think I follow you on how you got to the final equation (eliminating velocity)... let me try to put in some numbers and see what I get. Thanks for the help

Answer 8

u r welcome..:)

Answer 9

So, my final answer is 0.0516 ....meters? I think. Which would be 5.2 cm. Which is the answer I was looking for. I think this is correct. Again, thanks!!

Answer 10

:)