Electromagnetism And The Motor Effect

Question 1

what happens when a current flows through a long, straight conductor

Answer 1

a magnetic field is created around it

Question 2

what is the magnetic field created from a current flowing through a straight conductor made up of

Answer 2

concentric circles perpendicular to the wire, with the wire in the center

Question 3

what happens when you change the direction of the current flowing through a long, straight conductor

Answer 3

the direction of the magnetic field also changes

Question 4

how do you work out the direction of the flowing current from the direction of the magnetic field

Answer 4

• the right hand-thumb rule
• make a thumbs up and let your fingers be relatively loose
• the thumb shows the direction of the current
• the fingers show the circling direction of the magnetic field

Question 5

how would the strength of a magnetic field created from the a current flowing through a straight conductor be increased

Answer 5

• have a larger current flowing through the wire

- get closer to the wire

Question 6

what happens when a current-carrying conductor (wire) is put between magnetic poles

Answer 6

• the two magnetic fields from the two magnets interact

- this results in the creation of a force on the wire

Question 7

how would a full force be experienced with the motor effect

Answer 7

if the wire was perpendicular to the magnetic field

Question 8

what would happen if the wire ran along the magnetic field in the motor effect

Answer 8

the wire wouldnt experience any force at all

Question 9

how would the wire and magnet interact in the motor effect if the wire was at angle in between 0 and 90 to the magnet

Answer 9

the wire would exert an equal and opposite force on the magnet, so the wire would feel the same force

Question 10

where does the force always act in the motor effect

Answer 10

• in the same direction
• relative to the magnetic field
• and the direction of the current in the wire

Question 11

what would the effect of changing the direction of either the magnetic field or the current be in the motor effect

Answer 11

the direction of the force would change

Question 12

what is flemings left hand rule used for

Answer 12

finding the direction of the force on a current-carrying conductor

Question 13

what is flemings left hand rule

Answer 13

• use your left hand
• point your First finger in the direction of the magnetic Field
• point your seCond finger in the direction of the Current
• you thuMb will point in the direction oft he force (Motion)
• making the thumb motion, first finger field and second finger current

Question 14

what does the force acting on a conductor in a magnetic field depend on

Answer 14

• magnetic flux density
• size of the current through the conductor
• length of the conductor thats in a magnetic field

Question 15

what is magnetic flux density and what does it show

Answer 15

• how many field lines there are in a region

- shows the strength of the magnetic field

Question 16

what can be used to calculate the force when the current is at 90 degrees to the magnetic field it is in

Answer 16

• force = magnetic flux density x current x length

- F = B I l

Question 17

what are the units for force, magnetic flux density, current and length

Answer 17

force = N
magnetic flux density = T or N/Am
current = A
length = m

Question 18

when the motor effect is drawn, there will either be a dot or an x indicting the direction the wire is carrying the current. what does the dot and x indicate

Answer 18

• the dot represents a wire carrying current out of the page

- the x represents the wire carrying current into the page