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  • Magnetic field produced by a current segment.

Topics:  Magnetic field, Lenz's law, induced EMF, induced current, inductance..

Pre-requisite skills: Basic understanding of inductance, right-hand rule.

Approximate completion time:  Under an hour.

Provide sufficient detail to verify that the assignment was completed in a meaningful manner.

Applet by B. Surendranath Reddy

If the above applet fails to work properly, try the original site here.

The above applet depicts a current (on the left).  The direction of the arrow coincides with the direction of the current, defined as the flow of positive charge.   On the right is a square loop of wire.

1.  Using the mouse, slide the slider on the bottom-left to the right.  You will notice that an EMF symbol appears momentarily in the square loop.   

(a)  Explain its existence in terms of magnetic flux. 

(b) According to the orientation of the EMF symbol in the applet, which direction will the induced current in the square loop flow?  Explain why this is expected.


2.   Using the mouse, drag the square loop towards the current source.   Again, an EMF symbol will momentarily appear in the square loop.   As before:

(a)  Explain its existence in terms of magnetic flux. 

(b) According to the orientation of the EMF symbol in the applet, which direction will the induced current in the square loop flow?  Explain why this is expected.


3.   Now select the bottom-right corner of the square loop and, by dragging with the mouse, enlargen the loop.  One more time...

(a)  Explain its existence in terms of magnetic flux. 

(b) According to the orientation of the EMF symbol in the applet, which direction will the induced current in the square loop flow?  Explain why this is expected.

Helpful Resources

  1. The Biot-Savart Law by Fu Kwun Hwang.
  2. Biot-Savart Law Applications by Carl R. (Rod) Nave.
  3. Biot-Savart and Ampere's Laws by H. F. Cheung
  4. Magnetic Fields by Angel Franco Garcia.
  5. Loi de Biot-Savard (Biot-Savart) Law by Sibastien Bilodeau
  6. P10D - Electricity and Magnetism by Janak Sodha

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