Magnets - Shed Loads of Practice Questions
Fleming's Left Hand Rule Direction
In each case, use your left hand with your thumb representing the direction of the force, your index finger representing the direction of the magnetic field, and your middle finger representing the direction of the current.
Q1
A wire carrying a current flows from right to left in a magnetic field directed out the page. Use Fleming's Left Hand Rule to determine the direction of the force experienced by the wire.
Q2
In a magnetic field directed to the left, a current flows from bottom to top in a wire. Use Fleming's Left Hand Rule to find the direction of the force experienced by the wire.
Q3
A conductor carrying a current moves to the east in a magnetic field directed downward. Use Fleming's Left Hand Rule to determine the direction of the force acting on the conductor.
Q4
A current flows from top to bottom in a wire, and the magnetic field is directed to the right. Use Fleming's Left Hand Rule to find the direction of the force experienced by the wire.
Q5
A current-carrying conductor moves towards the west in a magnetic field directed upwards. Use Fleming's Left Hand Rule to determine the direction of the force acting on the conductor.
Q6
A wire carrying a current moves from east to west in a magnetic field directed into the page. Use Fleming's Left Hand Rule to find the direction of the force experienced by the wire.
Q7
In a magnetic field directed to the right, a current flows upwards in a wire. Use Fleming's Left Hand Rule to determine the direction of the force experienced by the wire.
Q8
A conductor carrying a current moves downwards in a magnetic field directed to the east. Use Fleming's Left Hand Rule to find the direction of the force acting on the conductor.
Q9
A current flows from bottom to top in a wire, and the magnetic field is directed out the page. Use Fleming's Left Hand Rule to determine the direction of the force experienced by the wire.
Q10
A current-carrying conductor moves upwards in a magnetic field directed to the left. Use Fleming's Left Hand Rule to find the direction of the force acting on the conductor.
Q11
A wire carrying a current moves from west to east in a magnetic field directed out the page. Use Fleming's Left Hand Rule to determine the direction of the force experienced by the wire.
Q12
In a magnetic field directed to the left, a current flows from upwards in a wire. Use Fleming's Left Hand Rule to find the direction of the force experienced by the wire.
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Q1
Upwards
Q2
Out the page
Q3
Out the page
Q4
Out the page
Q5
Into the page
Q6
Downward
Q7
Into the page
Q8
Out the page
Q9
To the right
Q10
Upward
Q11
Downward
Q12
Into the page
Calculating F = BIL
The formula F = BIL represents the force experienced by a current-carrying conductor in a magnetic field, where F is the force, B is the magnetic field strength, I is the current flowing through the conductor, and L is the length of the conductor.
Q1
A wire with a current of 2 A is placed perpendicular to a magnetic field of 0.5 T. If the wire's length is 0.3 m, what is the force experienced by the wire?
Q2
A conducting rod of length 0.4 m carries a current of 3 A and is placed in a magnetic field of 0.8 T. Calculate the force acting on the rod.
Q3
A wire of length 0.6 m is carrying a current of 4 A. If it experiences a magnetic field of 0.2 T, find the force acting on the wire.
Q4
A current-carrying wire of length 0.5 m is placed at an angle of 90 degrees to a magnetic field of 0.4 T. If the current in the wire is 2 A, calculate the force acting on the wire.
Q5
A straight conductor of length 0.8 m is placed perpendicular to a magnetic field of 0.6 T. If a current of 3 A flows through the conductor, find the force experienced by the conductor.
Q6
A wire carrying a current of 6 A is placed in a magnetic field of 0.4 T. If the wire's length is 0.5 m, what is the force experienced by the wire?
Q7
A wire of length 0.3 m is carrying a current of 8 A. If it experiences a magnetic field of 0.3 T, find the force acting on the wire.
Q8
A current-carrying wire of length 0.4 m is placed at an angle of 90 degrees to a magnetic field of 0.8 T. If the current in the wire is 3 A, calculate the force acting on the wire.
Q9
A straight conductor of length 0.6 m is placed perpendicular to a magnetic field of 0.2 T. If a current of 4 A flows through the conductor, find the force experienced by the conductor.
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Q1
0.3 N
Q2
0.96 N
Q3
0.48 N
Q4
0.4 N
Q5
1.44 N
Q6
1.2 N
Q7
0.72 N
Q8
0.96 N
Q9
0.48 N
Calculating Torque/Moment on Motor Wire
Remember that torque and a moment are the same thing. The equation for a moment is M = Fd, where M is the moment (torque), F is the perpendicular force acting on the wire and d is the wire’s distance from the pivot. This equation in combination with the equation F = BIL which will allow you to calculate the force can be combined to find the moment.
Q1
Inside a motor, a square loop of sides 0.2 m is carrying a current of 3 A. If it is placed perpendicular to a magnetic field of 0.6 T and the distance from the axis of rotation is 0.1 m, calculate the torque acting on the loop.
Q2
A square loop of sides 0.3 m carries a current of 4 A inside a motor. If it is placed perpendicular to a magnetic field of 0.8 T and the distance from the axis of rotation is 0.15 m, find the total torque on the loop.
Q3
Inside a motor, a square loop of sides 0.4 m carries a current of 5 A. If it is placed perpendicular to a magnetic field of 0.4 T and the distance from the axis of rotation is 0.2 m, calculate the torque on the loop.
Q4
Inside a motor, a wire of length 0.5 m carrying a current of 2 A is perpendicular to a magnetic field of 0.8 T. If the distance from the axis of rotation is 0.3 m, determine the torque experienced by the wire.
Q5
Inside a motor, a square loop of sides 0.3 m is carrying a current of 2 A. If it is placed at an angle of 90 degrees to a magnetic field of 0.5 T and the distance from the axis of rotation is 0.15 m, find the torque acting on the loop.
Q7
A square loop of sides 0.4 m carries a current of 3 A inside a motor. If it is placed perpendicular to a magnetic field of 0.7 T and the distance from the axis of rotation is 0.2 m, calculate the total torque on the loop.
Q8
Inside a motor, a wire of length 0.6 m carrying a current of 4 A is at an angle of 90 degrees to a magnetic field of 0.3 T. If the distance from the axis of rotation is 0.25 m, determine the torque experienced by the wire.
Q9
Inside a motor, a square loop of sides 0.4 m is carrying a current of 3 A. If it is placed at an angle of 90 degrees to a magnetic field of 0.6 T and the distance from the axis of rotation is 0.2 m, calculate the torque acting on the loop.
Q10
A square loop of sides 0.5 m carries a current of 4 A inside a motor. If it is placed perpendicular to a magnetic field of 0.8 T and the distance from the axis of rotation is 0.3 m, find the total torque on the loop.
Q11
Inside a motor, a wire of length 0.7 m carrying a current of 2 A is at an angle of 90 degrees to a magnetic field of 0.4 T. If the distance from the axis of rotation is 0.25 m, determine the torque experienced by the wire.
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Q1
0.072 Nm
Q2
0.288 Nm
Q3
0.32 Nm
Q4
0.24 Nm
Q5
0.09 Nm
Q7
0.336 Nm
Q8
0.18 Nm
Q9
0.288 Nm
Q10
0.96 Nm
Q11
0.14 Nm
Calculating Current and Voltage in a Transformer
Remember to use the transformer equation:
$( \frac{V_p}{V_s} = \frac{N_p}{N_s} = \frac{I_s}{I_p})$
Where: Vp = Primary voltage Vs = Secondary voltage Np = Number of turns in the primary coil Ns = Number of turns in the secondary coil Ip = Primary current Is = Secondary current
Q1
A transformer has 200 turns in the primary coil and 1000 turns in the secondary coil. If the primary voltage is 240 V, calculate the secondary voltage.
Q2
In a transformer, there are 1500 turns in the primary coil and 300 turns in the secondary coil. If the primary current is 5 A, find the secondary current.
Q3
A transformer has 800 turns in the primary coil and 4000 turns in the secondary coil. If the secondary voltage is 24 V, calculate the primary voltage.
Q4
In a transformer, there are 1200 turns in the primary coil and 600 turns in the secondary coil. If the secondary current is 2.5 A, find the primary current.
Q5
A transformer has 500 turns in the primary coil and 2500 turns in the secondary coil. If the primary voltage is 120 V, calculate the secondary voltage.
Q6
In a transformer, there are 2000 turns in the primary coil and 100 turns in the secondary coil. If the primary current is 8 A, find the secondary current.
Q7
A transformer has 600 turns in the primary coil and 3000 turns in the secondary coil. If the secondary voltage is 36 V, calculate the primary voltage.
Q8
In a transformer, there are 900 turns in the primary coil and 450 turns in the secondary coil. If the secondary current is 3 A, find the primary current.
Q9
A transformer has 300 turns in the primary coil and 1500 turns in the secondary coil. If the primary voltage is 200 V, calculate the secondary voltage.
Q10
In a transformer, there are 1800 turns in the primary coil and 300 turns in the secondary coil. If the primary current is 4 A, find the secondary current.
Q11
A transformer has 700 turns in the primary coil and 3500 turns in the secondary coil. If the secondary voltage is 42 V, calculate the primary voltage.
Q12
In a transformer, there are 1000 turns in the primary coil and 200 turns in the secondary coil. If the secondary current is 1.5 A, find the primary current.
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Q1
1200 V
Q2
25 A
Q3
4.8 V
Q4
1.25 A
Q5
600 V
Q6
160 A
Q7
48 V
Q8
1.5 A
Q9
1000 V
Q10
252 A
Q11
8.4 V
Q12
0.3 A