Electricity & Magnetism
Motional EMF
EMF induced in moving conductor.
Variables
εV
Induced EMF
Electromotive force
In SI units: kg·m²/(A·s³)
BT
Magnetic field
Field strength
In SI units: kg/(A·s²)
Lm
Length
Conductor length
Allowed values: greater than 0
vm/s
Velocity
Speed of conductor
Derivation
From Faraday's law: ε = -dΦ/dt = BL(dx/dt) = BLv.
Your notes
0/5000
Check value
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- B = 2 T (Magnetic field)
- L = 3 m (Length)
- v = 4 m/s (Velocity)
Result: ε = 24 V
Other electricity & magnetism formulas with the same quantities
- Magnetic Force on Charge (Magnetism) shares Velocity, Magnetic field
- Cyclotron Radius (Magnetism) shares Velocity, Magnetic field
- Self-Inductance (Electromagnetic Induction) shares Induced EMF
- Mutual Inductance EMF (Electromagnetic Induction) shares Induced EMF
- Magnetic Force on Wire (Magnetism) shares Magnetic field
- Magnetic Field (Long Wire) (Magnetism) shares Magnetic field
Where this formula is listed
- Electricity & Magnetism formulas, under Electromagnetic Induction, alongside Inductor Energy, RL Time Constant and Transformer Equation.
- In the electricity & magnetism list it comes after Magnetic Flux and before Self-Inductance.
- Electricity & Magnetism formula sheet, one of 48 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Motional EMF formula?
Motional EMF is written ℰ = BLv. EMF induced in moving conductor. It belongs to Electricity & Magnetism, under Electromagnetic Induction.
What are the units in ℰ = BLv?
In SI units, ε is induced emf, measured in kg·m²/(A·s³); B is magnetic field, measured in kg/(A·s²); L is length, measured in m; v is velocity, measured in m/s.
How is the Motional EMF formula derived?
From Faraday's law: ε = -dΦ/dt = BL(dx/dt) = BLv. The result is ℰ = BLv.