What Electric Field is Needed to Undeflect Electrons in a Magnetic Field?

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To undeflect electrons in a magnetic field, the electric field (E) must equal the magnetic force (F) acting on the electrons, which is determined by the equation E = vB. The electrons are accelerated through a potential difference of 11 kV, giving them kinetic energy that can be converted to velocity. The velocity can be calculated using the formula for kinetic energy, KE = (1/2)mv², where m is the mass of an electron. The magnetic field strength is given as 0.05 T, which is essential for determining the required electric field. Ultimately, the discussion focuses on finding the necessary electric field to achieve undeflected motion of the electrons in the specified magnetic field.
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A beam of electrons is accelerated through a potential difference of 11kV before entering a velocity selector. If the B-field of the velocity selector is perpendicular to the velocity and has a value of 0.05 T, what value of the E-field is required (in the magnetic field region) if the particles are to be undeflected?

What I know:
F = qvB
and
F = qE

Therefore E = vB

But how on Earth do I find the velocity? Please help!
 
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Stryker321 said:
But how on Earth do I find the velocity? Please help!

Read this again:
"A beam of electrons is accelerated through a potential difference of 11kV"
What energy will the electrons have?
 
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