Calculating Magnetic Force (Edexcel GCSE Physics)
Revision Note
Calculating Magnetic Force on a Current-Carrying Conductor
Higher Tier Only
The size of the force acting on a current-carrying wire in a magnetic field can be calculated using the equation:
F = BIL
Where:
F = force acting on current-carrying wire in newtons (N)
B = magnetic flux density (which is the strength of the magnetic field) in tesla (N/A m)
I = current flowing through the conductor in amps (A)
L = length of the conductor that is in the magnetic field in metres (m)
Force on a current carrying conductor (directed into the page)
Worked Example
A 5 cm length of wire is at 90o to the direction of an external magnetic field. When current of 1.5 A flows through the wire it experiences a force of 0.06 N from the motor effect. Calculate the magnetic flux density of the magnet.
N/A m = T
Answer:
Examiner Tips and Tricks
You will only be expected to calculate the force when the wire is perpendicular to the field, so you won't have to worry about angles.
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