Physics 2017 JAMB Past Questions - Question 5: How can energy loss be minimized through Eddy-current?

Correct Answer

B

Explanation

Eddy current is current induced in a sheet (orblock) of metal due to changing magnetic glux. By insulating the sheet of metalthe current is reduced
Eddy currents are circulating currents induced in a conductor when it is exposed to a changing magnetic field. These currents can lead to energy loss in the form of heat. To minimize energy loss through eddy currents, several techniques can be employed:

1. Use laminated or layered conductors: By using laminated or layered conductors, the path for eddy currents is interrupted, reducing their magnitude and minimizing energy loss. The layers are typically made of thin insulated sheets or coatings that prevent the flow of eddy currents between adjacent layers.

2. Utilize magnetic shielding: Magnetic shielding involves surrounding the conductor with a material that has high magnetic permeability, such as mu-metal. This shields the conductor from the external magnetic field, reducing the induction of eddy currents and minimizing energy loss.

3. Employ magnetic cores: In devices like transformers and inductors, using magnetic cores made of materials with low electrical conductivity, such as iron or ferrite, can help reduce eddy currents. These cores provide a preferred path for the magnetic flux, minimizing the formation of eddy currents in the conductive windings.

4. Optimize conductor geometry: The shape and size of the conductor can influence the magnitude of eddy currents. By designing conductors with smaller cross-sectional areas or using thin, flat conductors, the path for eddy currents is reduced, leading to lower energy loss.

5. Use higher resistivity materials: Choosing materials with higher resistivity, such as certain alloys or specialty conductors, can help reduce the magnitude of eddy currents and minimize energy loss. These materials impede the flow of eddy currents, converting more of the electrical energy into useful work.

It's important to note that the specific approach to minimize energy loss through eddy currents depends on the application and the desired trade-offs between cost, efficiency, and other factors. Consulting with experts in electrical engineering or magnetic field analysis can provide further guidance tailored to your specific needs.