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WorksheetsElectromagnetism
Total questions: 15
Worksheet time: 11mins
1. A magnetic field is produced by the current in a long straight wire. The strength of the magnetic field increases if.
The magnitude of the current increases
The distance from the wire increases
The length of the wire increases
1. Which of the following is true about the magnetic field
produced by a current in a circular coil?
It is uniform inside the coil
It is the weakest at the centre
It is the strongest at the centre
There is no magnetic field outside the coil
What is the effect of placing a piece of soft iron core inside a solenoid carrying current?
The resistance of the solenoid decreases
The current in the solenoid increases
The magnetic field becomes stronger
An electromagnet is used in these apparatus except
a telephone earpiece
an a.c dynamo
a compass
a moving coil ammeter
Which electromagnet is the strongest?
The figure shows a rectangular coil of wire WXYZ connected with a dry cell and a switch S is placed on the surface a horizontal table. Two compasses P and Q are laid on the wire WX and XY respectively.
What will happen to the pointer of compass P and Q when the switch ,S is closed?
P : North Q : North
P : North Q : East
P : South Q : East
P : South Q : West
Diagram below shows a copper wire coiled round a
U-shaped iron. Which of the following describes the magnetic pole of X, Y and Z correctly?
A
B
C
D
Which of the following change will decrease the magnetic effect of the iron rod?
Increase the current
Use a thicker wire to form the coil
Reduce the number of turns in the coil
Use a coil with a bigger cross-sectional area
The motion of a conductor carrying current in an magnetic fields can be determine by
Direction of current flow
Right hand Grip Rule
Fleming’s Right Hand Rule
Fleming’s Left Hand Rule
A current carrying wire is in between the poles of a magnet. The direction of the force on the wire is:
North
East
South
West
Two parallel wires are carrying equal currents in opposite directions. Which diagram shows the forces F on the wires?
P
Q
R
S
The function of the commutator in a d.c. motor is
to prevent the wires from entangling
to reverse the current in the coil at every half rotation
to enable the coil to be in electrical contact with
carbon brushes
Which Diagram shows the correct magnetic field pattern and direction of force due to current in a coil of d.c. motor that combine with magnetic field bar?
Which change will decrease the extension of springs?
Use a thicker conductor
Use a stronger magnet
Increase the number of batteries.
Increase the distance between magnet
Two soft iron rods are placed in the solenoid as shown in diagram (a). When current flows in the solenoid, what happen to the two rods ?
Both repel from each other
Both attracted
One moving out from solenoid
Both moving out from solenoid.
