Cambridge O Level Physics Revision!

Friday, October 09, 2009 / Posted by Honsbridge /

Dear Physics students,

For those who have registered their Cambridge O Level Exam at the British Council. Your Physics exam is just in three weeks time. If you have not gotten a copy of the Exam timetable, please find your time table hereAs I was doing revision on Electromagnetic induction with my class. My pupil, Joshua showed this torch to the class. I am excited to share with everyone who is learning this topic for the exam. In the diagram, it shows the application of Faraday's Law. That is when you shake the torch so that the magnet moves in and out of the solenoid. By Faraday's Law, an induced current is produced in the solenoid which is the coil of copper wires. The current induced could therefore power the torch in the absence of a battery or conventional power source. I hope this application of electromagnetic induction helps you picture the principle better.

Students who face difficulties in understanding the concept of electromagnetic induction, normally fail to understand what is a continuous change of linkage between the magnetic flux and the wires. In this example, one has to imagine that magnetic flux or field lines run from north to south pole of the magnet. These field lines of the magnet will cut the coil of wires as it moves in and out of the coil, in doing so there is a continuous change of linkage between the magnetic flux and the coil of wires. It is this change that results in current induced in the coil. By Faraday's Law, experiments have also shown that if a stronger magnet, more turns of wire on the solenoid and faster rate of change between the magnetic flux linkage and the wires, the more induced current is produced.

If you need any past year questions to work on, feel free to contact me and i will be happy to help you. Here is the very best of luck to all the students preparing hard for their exams!


Emma for Honsbridge

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