Discuss the effect on the magnitude of force on a current-carrying conductor

Motor Effect

• When a current carrying conductor passes through an external magnetic field, it experiences a force.
• This is known as the motor effect and was discovered by Michael Faraday in 1821.
• The direction of the 3 factors can be seen in the "Right hand palm/push rule", that is they are perpendicular to each other.

Factors that affect the magnitude of the force

• The strength of the external magnetic field (B) is proportional to the force.
• The magnitude of the current in the conductor (I) is proportional to the force.
• The length of the conductor in the field is proportional($l$) to the force.
• The angle between the conductor and the external magnetic field.
• This is what determines the conductor's effective length, or the vertical component of the length.
• Therefore it is given by $\sin{\theta}$ where $\theta$ is the angle to the field.
• The force is maximum when it is perpendicular(90゜) to the magnetic field
• The force is minimum when it is parallel (0゜) to the magnetic field.

This can be expressed mathematically as:

(1)
\begin{align} F = BIl\sin{\theta} \end{align}
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