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2.3.1 Magnetic fields Questions

1 Describe the use of Flemings left hand rule.

2 Copy the diagrams in fig. 2.3.8 and draw an arrow to show the direction of any force acting on the wire in

each case.

fig. 2.3.8

3 Many real motors use electromagnets to create the magnetic field that causes their rotor to spin. Gie one

adantage and one disadantage of building a motor which uses electromagnets rather than permanent

magnets.

7/25/2019 Topic 2 Pg63

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2.3.1 Magnetic fields Answers

1) !t is used to find the direction of a force on a current"carrying conductor in a magnetic field. #he thumbof the left hand indicates the direction of the force$ when the first finger is lined up with the magnetic

field and the second finger lined up with the current$ and these fingers and thumb all held at right angles

to each other in three dimensions.

2) a) Down b) !nto page c) %o force

3) &dantage' #he motor power can be altered for different applications.

Disadantage' !t is more comple( so there is more things to go wrong)brea*.