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50 questions
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?
What does the thumb indicate in flemings left hand rule?
Force
current
Magnetic field direction
What direction is the force/motion in the following diagram?
Perpendicular to the magnets
Downwards
Parallel and through the magnets
A represented by
direction of magnitude current
direction of force
direction of magnetic field
direction of rotation
Diagram shows a dc motor. What is the functions of brush carbon?
Push the brush so it will always contact with the commutator.
To contact with the commutator so the current from the battery enters the coil.
Reverse the direction of current in the coil every half rotation so that the coil continues to turn in same direction
Application of the force on current carrying conductor in a magnetic field
Moving coil ammeter
dynamo
Dc motor
electrIc bell
Dc generator
How can you test to see if there is a current running through a wire?
listen carefully to see if you hear a buzzing sound
place several compasses around the wire
place several batteries around the wire
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 ?
The motion of a current carrying conductor in an magnetic fields can be determined by
Right hand Grip Rule
Fleming’s Right Hand Rule
Fleming’s Left Hand Rule
Direction of current flow
Diagram above shows the apparatus used to set-up to observe the magnetic field due to a current in a coil.
A current-carrying coil in a magnetic field experiences a turning effect.
How can the turning effect be increased?
increase the number of turns on the coil
reduce the size of the current
reverse the direction of the magnetic field
use thinner wire for the coil
The diagram shows an electrical device. What is this electrical device?
a d.c. motor
an a.c. generator
a magnetising coil
a transformer
The diagram shows a coil of wire between the poles of a magnet.
The coil consists of 20 turns of insulated wire.
The coil is connected to a variable resistor and a power supply.
How can the turning effect on the coil be increased?
by moving the poles of the magnet closer to the coil
by reducing the number of turns on the coil while keeping the current constant
by increasing the resistance of the variable resistor
by reversing the terminals of the power supply
What happens to the strength of a magnetic field as you move away from the magnet?
The strength of the magnetic field increases.
The strength of the magnetic field doesn't change.
The strength of the magnetic field is doubled.
The strength of the magnetic field decreases.
"a region around a magnetic material or a moving electric charge within which the force of magnetism acts".
This is definition of
magnetic field
magnetic charge
magnet
electromagnet
For the right hand grip rule for a solenoid: The thumb points towards ________ of the magnetic field while
positive pole
south pole
north pole
negative pole
All of the following are application of electromagnet EXCEPT
microphone
circuit breaker
electric bell
ear phone
Fleming's left hand rule used to determine
direction of electric current
direction of pole
direction of magnetic force
direction of magnetic field
When a current-carrying conductor is in a magnetic field of a permanent magnet, the interaction between the two magnetic fields produce ___________.
a current on the conductor
a force on the conductor
a electricity on the conductor
a pole on the conductor
The magnitude of the force on a current carrying conductor in a magnetic field can be increase by all of the following EXCEPT
use longer wire
increase current
use stronger permanent magnet
use wire with larger cross sectional area
The application of catapult effect is
microphone
generator
electric bell
direct current motor
The diagram show the direction of magnetic field,B and current, I.
By using Fleming left hand rules, determine the direction of Magnetic force, F.
no force produced
right
into the page
out from the page
The diagram show the direction of magnetic field,B and current, I.
By using Fleming left hand rules, determine the direction of Magnetic force, F.
no force produced
right
downward
out from the page
Which part (s) of the DC motor connect the power supply to the split-ring and coil?
Carbon brushes
Magnets
Commutator
Slip rings
Use Flemming's left-hand rule to work out which way coil AB will turn.
Downward
Upward
Into the paper
Out of the paper
What advantage does an electromagnet have over a magnet?
It can be switched on and off
It is stronger
It is easier to change shape
What is the direction of the force on the wire due to the magnetic field?
To the right
Downward
To the left
Out of the screen
Diagram below shows a current-carrying conductor in a magnetic field.
J
K
L
M
Diagram below shows the apparatus used to study the effect of an electromagnet.
Which change will increase the number of paper clips attracted to the iron rod?
Use a thinner wire to form the coils
Use a non-insulated wire to form the coils
Reduce the number of coils
Increase the magnitude of the current
Diagram 32 shows a design of a simple circuit breaker. It is designed to prevent an electrical circuit from damage caused by excessive current or short circuit.
Which statement is the best to explain why the iron armature should be made of iron?
Its strong and magnetic material
Its magnetic material and has high melting point
Its strong and a good conductor of heat
Its flexible and a good electrical conductor
Which magnetic field produced by a straight current-carrying conductor is correct?
Diagram below shows four identical compasses placed around a conductor.
The switch is switched on and current passes through the conductor.
In which direction do the compasses P, Q, R and S show the direction of the magnetic field?
A
B
C
D
Diagram below shows an electric motor.
The magnitude of force F increases when
the number of turns of the wire coil decreases
the magnitude of the electric current decreases
the magnitude of the magnetic field decreases
the resistance of the wire coil decreases
Diagram below shows a conductor wire placed in a magnetic field.
When the switch is on, the conductor wire initially moves towards
W
X
Y
Z
Diagram below shows a solenoid.
Which of the following rules may be used to determine the direction of the current in the coil?
A Fleming’s Left Hand Rule
Fleming’s Right Hand Rule
Right Hand Screw Rule
Right Hand Grip Rule
Diagram shows a left hand which represents the Fleming Left-Hand Rule.
X represents the
motion
current
magnetic field
potential difference
Diagram below shows a conductor placed inside a magnetic field.
What is the direction of motion of the conductor when the current flows?
W
X
Y
Z
Diagram below shows the apparatus set-up to observe the magnetic field due to a current in a coil.
Which diagram shows the magnetic field correctly?
Which diagram shows the pattern of the magnetic field produced by a straight conductor carrying current?
The diagram below shows a straight conductor placed in a magnetic field. Both of the soft springs extend when the switch is on.
Which change will decrease the extension of the springs?
Use a stronger magnet
Use a thicker conductor
Increase the number of batteries
Increase the distance between magnets
The diagram below shows a wire QR hangs freely between two strong magnets.
The angle of deflection, θ is increased by
increasing the current
changing the polarity of the magnet
increasing the resistance of the wire QR
increasing the distance between the poles of the magnet
Diagram 29 shows the apparatus set up by a student in order to make a relay.
Which metal should be used to make the core?
Aluminium
Copper
Soft iron
Steel
Diagram 31 shows a current-carrying wire between the poles of a pair of permanent magnets.
What is the direction of the force on the wire?
A
B
C
D
Diagram 20 shows the direction of movement of a current carrying conductor that is placed between two magnets.
Which magnetic field pattern is correct to show the situation?
Which diagram shows the correct combination of forces when the magnetic field due to the current in the coil combines with the external magnetic field?
Which diagram shows the correct rule to determine the magnetic field around a straight wire?
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