Hello I am Here to present an important topic and most exciting topic
 |
| Electromagnetism |
Force on a Current-carrying Conductor Lying in a Magnetic Field
It is found that whenever a current-carrying conductor is placed in magnetic field, it experiences a
force which acts in a direction perpendicular both to the direction of the current and the field. In Fig
. is shown a conductor XY lying at right angles to the uniform horizontal field of flux density B Wb
/m2
produced by two solenoids A and B. If l is the length of the conductor lying within this field and
I ampere the
current carried by it, then the magnitude of the force experienced by it is
the BIl = µ0 µr HIl newton
Using vector notation
F
= I l B
F = IlB sin θ where θ is the angle between l
which
is 90º in the present case
or F = Il B sin 90º = Il B newtons (∵ sin 90º = 1)
The direction of this force may be easily found by Fleming’s left-hand rule.
Hold out your left hand with forefinger, second finger and thumb at right angles to one another.
If the forefinger represents the direction of the field and
If the forefinger represents the direction of the field and
the second finger that of the current, then thumb gives the direction
of the motion. It is illustrated in Fig.
shows another method of finding the direction of force acting on a current carrying conductor. It is
known as Flat Left Hand rule. The force acts in the direction of the thumb obviously, the direction of motor of the
of the field, then B can be resolved into two components,
B cos θ parallel to and B sin θ perpendicular to the conductor. The former produces no effect whereas the latter is
responsible for the motion observed. In that case,
F = BIl sin θ newton, which has been expressed as
cross product of vector above.
known as Flat Left Hand rule. The force acts in the direction of the thumb obviously, the direction of motor of the
conductor is the same as that of the force. It
should be noted that no force is exerted on a conductor when it lies parallel to the magnetic field. In general, if the conductor lies at an angle θ with the direction
B cos θ parallel to and B sin θ perpendicular to the conductor. The former produces no effect whereas the latter is
responsible for the motion observed. In that case,
 |
| Fleming left hand rule |
F = BIl sin θ newton, which has been expressed as
cross product of vector above.
0 comments: