Uniform electric and magnetic field

[aiika]

Homework Statement

a particle with initial velocity Vo=6.00 x10r^3 m.s-1 in the +x direction enters a region of uniform electric and magnetic fields. the magnetic field in the region is B=0.300 T in the -y direction. calculate the magnitude and direction of the electric field in the region if the particle passes through undeflected for a particle
a) +0.400x 10raise to -8 C
b)-0.400x 10 raise to -8 C

Homework Equations

can i use the Lorentz Force Law

F=qE+qvxB

The Attempt at a Solution

i'm stuck and i don't know how to start. HELP please.it will be higly appreciated :D

Thanks in advance

 

[tiny-tim]

welcome to pf!

hi aiika! welcome to pf!

(try using the X² icon just above the Reply box )

Yes, use Lorentz Force …

how much does the qE have to be to cancel out the qvxB so as to produce a zero deflection?

 

[aiika]

hi there..i tried using this

qE=qvxB

hmmm..am i on the right track?

 

[tiny-tim]

wouldn't qE = -qvxB work better?

 

[aiika]

oh thanks!

so...

with qE what should i do next?

 

[tiny-tim]

uhh?

get on with it!​