# Please help me with this physic excercise as soon as possible.

Printable View

• Apr 29th 2008, 07:00 AM
blertta
Please help me with this physic excercise as soon as possible.
A charged particle that moves with the speed v=8x10(7) goes in a magnetic field where B=0.7 T (B is the induction) and it makes an angle λ=45◦ with force lines. How is the specific charge (q/m) if the radius is R=4 cm?
(qvb =mv2/R qvb is the formula of the Lorenz force and mv2/R is the centripetal.)
Sorry for my english!
• Apr 29th 2008, 07:23 AM
topsquark
Quote:

Originally Posted by blertta
A charged particle that moves with the speed v=8x10(7) goes in a magnetic field where B=0.7 T (B is the induction) and it makes an angle λ=45◦ with force lines. How is the specific charge (q/m) if the radius is R=4 cm?
(qvb =mv2/R qvb is the formula of the Lorenz force and mv2/R is the centripetal.)
Sorry for my english!

I assume by force lines you mean the magnetic field lines?

$q \vec{v} \times \vec{B} = qvB~sin(45)$

so
$qvB~sin(45) = \frac{mv^2}{R}$

$\frac{q}{m} = \frac{v}{RB~sin(45)}$

-Dan