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Questions
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?
Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally towards the front wall from the back wall, is deflected by a strong magnetic field to your right side. Find the direction of the magnetic field.
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Solution
The direction of the magnetic field is vertically downward. The direction of current is from the front wall to the back wall because negatively charged electrons are moving from the back wall to the front wall. The direction of magnetic force is rightward. Hence, using Fleming’s left-hand rule, it can be concluded that the direction of the magnetic field inside the chamber is downward.
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