In the moving iron meter movement, what effect do the bars of iron in the radial vane exhibit when current flow increases?

The correct choice is based on the principles of magnetism and the operation of moving iron meters. In a moving iron meter movement, the iron bars are designed to respond to the magnetic fields generated by the current flow. When the current increases, it creates a stronger magnetic field, which influences the iron bars.

The specific behavior of the bars of iron in this context is one of repulsion. As the magnetic field strength increases, it causes the iron vane to move in response to the increased magnetic pull. This movement directly relates to the design of the meter, which utilizes the interaction between the magnetic field and the iron components to measure the current accurately. The repulsive effect contributes to the deflection of the meter needle, allowing it to reflect the amount of current flowing through the circuit.

Understanding this response is fundamental for linemen, as it illustrates how electrical measurements are objectively reflected in the performance of electrical meters. The phenomenon showcases the principles of electromagnetic interaction while providing a practical application in line work and electrical maintenance.