This paper features an indirect method to measure the speed of light. First, the electrical permittivity of air ε0, is obtained, by using a capacitance meter to measure the capacitance of a parallel-plate capacitor, by varying the separation between its plates. By means of a least squares adjustment, the slope of the straight line is calculated which is related to ε0.
Next, the magnetic permittivity of air μ0 is obtained by using a solenoid through which different currents are circulated and the magnetic field is measured in its centre using the Hall sensor of a Smartphone. By means of a least squares adjustment, the slope of the straight line is calculated which is related to μ0.
Once ε0 and μ0 have been obtained, the speed of light is calculated by the expression with its corresponding absolute and relative errors, to verify if the obtained value is compatible with the exact value of c.
Keywords
Physics Laboratory
Active Physics
Capacitance
Magnetic Field
Permittivity
Permeability
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