Physics Review Question Unit: Electricity and Magnetism Year: 1996 Question#: 33 Question: The diagram at the right shows an electron current in a wire loop. What is the direction of the magnetic field at the center of the loop? (1 ) out of the page (2 ) into the page (3 ) clockwise (4 ) counter clockwise What is this question really asking? Explanation by: Becky G [ Return to question menu ] Answer 1 Out of the page CORRECT When applying the hand rules to an electric current flowing through this wire,the magnetic field can be seen to emerge from the center of the loop and return into the page on the outside of the loop. Remember, using the left hand (because of the negative charge) place your thumb in the direction of the moving charge fingers wrap around the wire in the direction of the field. return to top Answer 2 into the page INCORRECT When applying the hand rules to this diagram the magnetic current can be seen to emerge from the inside of the loop, thus it is traveling out of the page, not into the page. Remember, using the left hand (because of the negative charge) place your thumb in the direction of the moving charge fingers wrap around the wire in the direction of the field. return to top Answer 3 clockwise INCORRECT Magnetic fields point perpendicular to the direction of the current. If the current is traveling in a clockwise direction, the magnetic field must be pointing into or out of the page. Remember, using the left hand (because of the negative charge) place your thumb in the direction of the moving charge fingers wrap around the wire in the direction of the field. return to top Answer 4 counterclockwise INCORRECT Magnetic fields point perpendicular to the direction of the current. If the current is traveling in a clockwise direction, the magnetic field must be pointing into or out of the page. Remember, using the left hand (because of the negative charge) place your thumb in the direction of the moving charge fingers wrap around the wire in the direction of the field. return to top What's this question really asking? This question is really asking if you can use the first hand rule properly. return to top |
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