In this experiment designed for use with PASCO Capstone software, the dependence of the magnetic field strength of current-carrying coils on the distance from the coil along the perpendicular axis is determined and compared to the theoretical curve. In addition, the effect of varying the coil separation on the shape of the magnetic field between the Helmholtz coils is examined.
The magnetic fields of various coils are plotted versus position as the Magnetic Field Sensor is passed through the coils, guided by a track. The position is recorded by a string attached to the Magnetic Field Sensor that passes over the Rotary Motion Sensor pulley to a hanging mass.
It is particularly interesting to compare the field from Helmholtz coils at the proper separation of the coil radius to the field from coils separated at less than or more than the coil radius.
The magnetic field inside a solenoid can be examined in both the radial and axial directions.
Using PASCO Capstone's curve fit, the theoretical equation for the magnetic field can be plotted on the same graph.
This plot shows the magnetic field strength along the axis of Helmholtz coils for three different coil separations. The green data is for coils with the proper separation (the coil radius), the red data is for the coils too close together, and the blue data is for the coils too far apart. The green curve is the measured magnetic field versus distance along the perpendicular axis of a single coil. The red theoretical curve is plotted from an equation.