A point Charge in an External Electric Field

 

Let a point charge q with an initial velocity vo enter a region where a uniform electric field E exists. Let q be the angle between vo and E What will be the subsequent motion of the point charge ?

 

Situation

Negative Charge

Positive Charge

 

vo = 0

Accelerate opposite to E

Accelerate in the direction of E

q = 0 (vo and E are parallel )

·        Decelerate

·        Stop momentarily

·        Reverse direction

·        Depends on the length of the region where E exists

Continue moving in the same direction with acceleration

q = 180o ( vo and E are anti-parallel )

Continue moving in the same direction with acceleration

·        Decelerate

·        Stop momentarily

·        Reverse direction

·        Depends on the length of the region where E exists

0 < q < 180

Projectile motion

Projectile motion