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20 questions
Magnetic field produced around a straight conductor due to current in it is given by
Fleming's right hand rule
Right hand grip rule
Clock rule
Fleming's left hand rule
b) based on the diagram above, choose the direction of the forces that act on the sides AB and CD of the coil.
AB:UPWARD;CD:DOWNWARD
AB:DOWNWARD;CD:UPWARD
c) What is the rule that is used to determine the direction of the force that acts on the coil?
The figure shows the structure of a motor. Which of the following will not affect the speed of rotation of the motor?
The current in the coil
Strength of the magnetic field
The number of turns of wire in the coil
The direction of the current in the coil
Figure 1 and Figure 2 show the structures of a d.c motor and a d.c. motor respectively. State the change of energy that occurs in a motor.
Electrical energy to kinetic energy
Kinetic energy to electrical energy
What does the thumb indicate in flemings left hand rule?
Force
Motion
Current
Magnetic field direction
Name one factor that does not affect the size of a force in on a current-carrying conductor placed in a magnetic field?
Gravity
Magnetic flux density/size of magnetic field
Size of the current
Length of the conductor
Why might a current-carrying wire be placed between a magnetic field?
To increase the current from the interaction of magnetic fields
To increase the voltage from the interaction of magnetic fields
To produce a force from the interaction of magnetic fields
c represented by
direction of magnetic field
direction of rotation
direction of force
direction of magnitude current
What is the functions of commutator?
Reverse the direction of current in the coil every half rotation so that the coil continues to turn in same direction
To contact with the commutator so the current from the battery enters the coil.
Push the brush so it will always contact with the commutator.
Diagram shows a coil placed between the poles of a permanent magnet and is connected to the external circuit.Determine the direction of rotation of the coil when the switch is closed.
Clock wise
Anti Clock wise
Alternately, anticlockwise then clockwise
Alternately, clockwise then anticlockwise
Diagram shows a coil placed between two opposite magnetic poles. An electric current flows through the coil producing a pair of turning force, F.Which diagram shows the correct catapult field ?
Diagram shows a current–carrying conductor placed between the poles of two magnet bars. Which diagram shows the resulting magnetic field ?
Diagram shows a current – carrying conductor in magnetic field. What is the direction of the force that acts on the conductor ?
A
B
C
D
The speed of direct current motor can be reduced by
increasing the amount of current
increasing the strength of magnet
increasing number of turns of coil
increasing the resistance of coil wire
A wire carries a current, creating a magnetic field around itself as shown. The current in the wire is:
Directed to the right
Directed to the left
Equal to the magnetic field
In the same direction as the magnetic field
What does the following represent?
⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗
⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗
⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗⊗
Multiplied by a billion
A piece of modern art
Uniform magnetic field directed into the screen away from you
Uniform magnetic field directed out of your screen at you
The strongest part of a magnet is...
the bars .
the force field.
the poles.
the middle.
A current carrying wire lies between the poles of
two magnets, as shown. What is the direction of the force on the wire?
Into the plane of the paper
Out of the plane of the paper
Towards the N-pole
To the right
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