the motor effect (combined science

Question 1

what is the motor effect

Answer 1

when a current-carrying conductor is placed in a magnetic field it experiences a force

Question 2

how is the motor effect caused

Answer 2

the motor effect is caused by the feild created by the current interacting with the magnetic feild

Question 3

how can the force be increased

Answer 3

increasing the size of the current

increasing the length of conductor in the magnetic field

increasing the flux density

Question 4

what will happen if current or magnetic field is reversed

Answer 4

reversing the direction of either the current or the magnetic field will cause the direction of the force to reverse

Question 5

what happens when there are several cells

Answer 5

several cells produce a big current and therefore a large force

Question 6

what do stronger magnets do

Answer 6

a large force can also be produced with stronger magnets, giving a higher flux density

Question 7

what happens when we reverse the cell

Answer 7

reversing the cell reverses the current and so reverses the forces

Question 8

what happens when we reverse the magnets

Answer 8

reversing the magnets reverses the field and so reverses the direction

Question 9

how is the direction of the force found

Answer 9

the direction of the force on the conductor can be found using Flemings left hand rule t

Question 10

describe Flemings left-hand rule

Answer 10

hold the left hand so that the thumb, first finger and second finger are all right angles to one another

align the first finger so that it points in the direction of the magnetic feild, from north to south.

rotate the wrist so that the second finger points along the wire in the direction current is flowing

the thumb will be pointing in the direction of the force

Question 11

what can the left hand rule be used for

Answer 11

the left-hand rule can be used to find the direction of either field, current or movement as long as the other two are known

Question 12

what happens to a current-carrying coil in a magnetic field and why

Answer 12

a current-carrying coil in a magnetic field will rotate

this is because the current going up one side of the coil is in the opposite direction to the current coming back down the other side, so one side moves up and the other moves down

this is the basis of an electric motor, which is designed so that the coil rotates continuously

Question 13

what does the brush do in a coil

Answer 13

the brush contacts at the commutator ensure that the current direction in the coil is always in the same direction

this ensures that the motor continues rotating and does not simply stop in the upright position

Question 14

how can Flemings left-hand rule used on a coil

Answer 14

Fleming left hand rule can be used on one side of the coil to work out which direction the motor will rotate

Question 15

what does increasing the current or magnetic field do to a motor

Answer 15

increasing the current or the magnetic field will make the motor rotate faster

Question 16

what does reversing the current or magnetic field do to the motor

Answer 16

reversing the current or the magnetic field will make the motor rotate in the opposite direction