Electricity and Magnetism Flashcards
Magnetic flux can always be
attributed to:
Motion of charged particles
A straight conductor 500 mm long is
moved with constant velocity at right
angles both to its length and to a
uniform magnetic field. Given that
the e.m.f. induced in the conductor is
2.5 V and the velocity is 5 m/s,
calculate the flux density of the
magnetic field. If the conductor forms
part of a closed circuit of total
resistance 5 ohms, calculate the force
on the conductor.
0.25 N
Which of the following statements is
true?
Like charges repel each other.
Unlike charges attract each
other.
A changing magnetic field:
Produces a fluctuating electric
field.
. For the current carrying conductor
lying in the magnetic field shown in
the figure below, the direction of the
force on the conductor is:
downwards
A conductor of length 15 cm is moved
at 750 mm/s at right-angles to a
uniform flux density of 1.2 T.
Determine the e.m.f. induced in the
conductor.
. 0.135 V
Which is the wrong statement? The
magnetizing force at the center of a
circular coil varies
directly as the number of its
turns
A 25 cm long conductor moves at a
uniform speed of 8 m/s through a
uniform magnetic field of flux
density 1.2 T. Determine the current
flowing in the conductor when its
ends are connected to a load of 15
ohms resistance.
0.16 A
Two bar magnets are placed parallel
to each other and about 2 cm apart,
such that the south pole of one
magnet is adjacent to the north pole
of the other. With this arrangement,
the magnets will:
attract each other
A car is travelling at 80 km/h.
Assuming the back axle of the car is
1.76 m in length and the vertical
component of the earth’s magnetic
field is 40 T, find the e.m.f.
generated in the axle due to motion.
1.56 mV
Calculate the current required in a 240
mm length of conductor of a d.c.
motor when the conductor is situated
at right-angles to the magnetic field of
flux density 1.25 T, if a force of 1.20
N is to be exerted on the conductor.
4 A
If a neutral atom loses one of its
valence electrons, it becomes a (n)
electrically charged atom.
positive ion.
For the current-carrying conductor
lying in the magnetic field shown in
the figure below, the direction of the
current in the conductor is:
towards the viewer
A conductor 300 mm long carries a
current of 13 A and is at right-angles
to a magnetic field between two
circular pole faces, each of diameter
80 mm. If the total flux between the
pole faces is 0.75 mWb, calculate the
force exerted on the conductor.
0.582 N
Which of the following statements is
true?
Like charges repel each other.
Unlike charges attract each other.
Calculate the force exerted on a
charge of 2x10-18 C travelling at
2x106 m/s perpendicular to a field of
density 2x10-7 T.
8.0 x 10-19 N
. The most basic particle of negative
charge is the ____.
electron
Aluminum, with an atomic number
of 13, has
3 valence electrons.
13 protons in its nucleus.
The nucleus of an atom is made up
of
neutrons and protons.
One ampere of current corresponds to
1 C/1 s
Conventional current is considered
the motion of positive charges in
the opposition direction of
electron flow.
The coulomb is a unit of
electric charge.
A conductor 30 cm long is situated at
right-angles to a magnetic field.
Calculate the flux density of the
magnetic field if a current of 15 A in
the conductor produces a force on it
of 3.6 N
0.80 T
The coulomb is a unit of:
Quantity of electricity
