1. AP Physics L12_Hall Magnetic + Electric field
Force on a charge
Magnetic + Electric field

2. Total Force F = q (E + vB) When does the force vanish?
AP Physics L12_Hall
Total Force
F = q (E + vB)
When does the force vanish?
Why is this called a velocity selector?
When E is in the direction of –v x B. So E must be perpendicular to B.
What are the units of vB?
What are the units of E/B?

3. The Hall Effect

4. Current through a Field
Charge carriers experience a force B I
Where do moving charges congregate?

5. Positive charge carriers
Positive charges accumulate B V I
Set up an E field ↓
Voltage across the ribbon

6. Negative charge carriers
Negative charges accumulate B V I
− − − − − − − − − − − − − − − − −
− − − − − − − − −
Set up an E field ↑
Voltage across the ribbon

7. Uses of Hall Effect Determine sign of charge of charge carrier
Measure drift velocity
Determine charge carrier density