Chapter 13 - Magnetic Effects of Electric Current, Class 10, Science PDF Download

 Page 1


In this chapter, we will study the effects of electric current :
1. Hans Christian Oersted (1777-1851)
Oersted showed that electricity and magnetism are related to each other. His 
research later used in radio, television etc.
The unit of magnetic field strength is name Oersted in his honour.
2. Oersted Experiment
CHAPTER – 13
MAGNETIC EFFECTS OF 
ELECTRIC CURRENT
– +
Y
X
R K
XY is conductor (Cu wire)
through which current is passed
On passing the current through the copper wire XY in the circuit, the compass 
needle which is placed near the conductor gets deflected. If we reverse the 
direction of current, the compass needle deflect in reverse direction. If we 
stop the flow of current, the needle comes at rest.
Hence, it conclude that electricity and magnetism are linked to each other. It 
shows that whenever the current will flow through the conductor, then 
magnetic field around. it will developer
3. Magnetic Field – It is the region surrounding a magnet, in which force of 
magnet can be detected. It is a vector quantity, having both direction & 
magnitude.
4. Compass needle– It is a small bar magnet, whose north end is pointing 
towards north pole and south end is pointing towards south pole of earth.
5. Magnetic field lines–
When a bar magnet is placed on a card board and iron fillings are sprinkled, 
they will arrange themselves in a pattern as shown below.
X-Science
137
Page 2


In this chapter, we will study the effects of electric current :
1. Hans Christian Oersted (1777-1851)
Oersted showed that electricity and magnetism are related to each other. His 
research later used in radio, television etc.
The unit of magnetic field strength is name Oersted in his honour.
2. Oersted Experiment
CHAPTER – 13
MAGNETIC EFFECTS OF 
ELECTRIC CURRENT
– +
Y
X
R K
XY is conductor (Cu wire)
through which current is passed
On passing the current through the copper wire XY in the circuit, the compass 
needle which is placed near the conductor gets deflected. If we reverse the 
direction of current, the compass needle deflect in reverse direction. If we 
stop the flow of current, the needle comes at rest.
Hence, it conclude that electricity and magnetism are linked to each other. It 
shows that whenever the current will flow through the conductor, then 
magnetic field around. it will developer
3. Magnetic Field – It is the region surrounding a magnet, in which force of 
magnet can be detected. It is a vector quantity, having both direction & 
magnitude.
4. Compass needle– It is a small bar magnet, whose north end is pointing 
towards north pole and south end is pointing towards south pole of earth.
5. Magnetic field lines–
When a bar magnet is placed on a card board and iron fillings are sprinkled, 
they will arrange themselves in a pattern as shown below.
X-Science
137
X-Science
138
N S
The lines along which the iron filling align themselves represent magnetic 
field lines.
Hence, magnetic field line is a path along which a hypothetical free north pole 
tend to move towards south pole.
6. Characteristics of Magnetic field lines :
(1) The direction of magnetic field lines outside the magnet is always from 
north pole to south pole of bar magnet and are indicated by an arrow.
Inside the magnetic, the direction of field lines is from its south pole to north 
pole
Thus magnetic field lines are closed curve
(2) The strength of magnetic field is expressed by the closeness of magnetic 
field lines. Closer the lines, more will be the strength and farther the lines, less 
will be the magnetic field strength.
(3) No two field lines will intersect each other.
If they intersects, then at point of intersection the compass needle will show 
two direction of magnetic field which is not possible.
Tangent at the
point of intersection
shows two direction.
7. Magnetic field due to Current Carrying Conductor
+ –
(a)
x
N
S
y
Cu wire
+ –
(b)
x
N
S
y
Cu wire
Page 3


In this chapter, we will study the effects of electric current :
1. Hans Christian Oersted (1777-1851)
Oersted showed that electricity and magnetism are related to each other. His 
research later used in radio, television etc.
The unit of magnetic field strength is name Oersted in his honour.
2. Oersted Experiment
CHAPTER – 13
MAGNETIC EFFECTS OF 
ELECTRIC CURRENT
– +
Y
X
R K
XY is conductor (Cu wire)
through which current is passed
On passing the current through the copper wire XY in the circuit, the compass 
needle which is placed near the conductor gets deflected. If we reverse the 
direction of current, the compass needle deflect in reverse direction. If we 
stop the flow of current, the needle comes at rest.
Hence, it conclude that electricity and magnetism are linked to each other. It 
shows that whenever the current will flow through the conductor, then 
magnetic field around. it will developer
3. Magnetic Field – It is the region surrounding a magnet, in which force of 
magnet can be detected. It is a vector quantity, having both direction & 
magnitude.
4. Compass needle– It is a small bar magnet, whose north end is pointing 
towards north pole and south end is pointing towards south pole of earth.
5. Magnetic field lines–
When a bar magnet is placed on a card board and iron fillings are sprinkled, 
they will arrange themselves in a pattern as shown below.
X-Science
137
X-Science
138
N S
The lines along which the iron filling align themselves represent magnetic 
field lines.
Hence, magnetic field line is a path along which a hypothetical free north pole 
tend to move towards south pole.
6. Characteristics of Magnetic field lines :
(1) The direction of magnetic field lines outside the magnet is always from 
north pole to south pole of bar magnet and are indicated by an arrow.
Inside the magnetic, the direction of field lines is from its south pole to north 
pole
Thus magnetic field lines are closed curve
(2) The strength of magnetic field is expressed by the closeness of magnetic 
field lines. Closer the lines, more will be the strength and farther the lines, less 
will be the magnetic field strength.
(3) No two field lines will intersect each other.
If they intersects, then at point of intersection the compass needle will show 
two direction of magnetic field which is not possible.
Tangent at the
point of intersection
shows two direction.
7. Magnetic field due to Current Carrying Conductor
+ –
(a)
x
N
S
y
Cu wire
+ –
(b)
x
N
S
y
Cu wire
The above electric circuit in which a copper is placed paralled to a compass 
needle, shows the deflection in needle gets reversed, when the direction of 
current reversed. Hence electricity and magnetism are related to each other.
8. Right Hand Thumb Rule :–
It is a convenient way of finding the direction of magnetic field associated 
with current carrying conductor.
Hold the straight were carrying current in your right hand such that thumb 
points towards the direction of current, then your folded fingers around the 
conductor will show the direction of magnetic field.
Direction of magnetic
field lines.
This rule is also called Maxwell’s corkscrew rule.
9. Magnetic Field due to Current through a Straight Conductor
A
+ –
+ –
Pheostat
Direction of
Current
Direction
of magnetic
field
Direction can be 
explained using 
Right Hand Thumb 
Rule
10. Magnetic Field due to Current through a circular Loop
+
–
Z S
X-Science
139
Page 4


In this chapter, we will study the effects of electric current :
1. Hans Christian Oersted (1777-1851)
Oersted showed that electricity and magnetism are related to each other. His 
research later used in radio, television etc.
The unit of magnetic field strength is name Oersted in his honour.
2. Oersted Experiment
CHAPTER – 13
MAGNETIC EFFECTS OF 
ELECTRIC CURRENT
– +
Y
X
R K
XY is conductor (Cu wire)
through which current is passed
On passing the current through the copper wire XY in the circuit, the compass 
needle which is placed near the conductor gets deflected. If we reverse the 
direction of current, the compass needle deflect in reverse direction. If we 
stop the flow of current, the needle comes at rest.
Hence, it conclude that electricity and magnetism are linked to each other. It 
shows that whenever the current will flow through the conductor, then 
magnetic field around. it will developer
3. Magnetic Field – It is the region surrounding a magnet, in which force of 
magnet can be detected. It is a vector quantity, having both direction & 
magnitude.
4. Compass needle– It is a small bar magnet, whose north end is pointing 
towards north pole and south end is pointing towards south pole of earth.
5. Magnetic field lines–
When a bar magnet is placed on a card board and iron fillings are sprinkled, 
they will arrange themselves in a pattern as shown below.
X-Science
137
X-Science
138
N S
The lines along which the iron filling align themselves represent magnetic 
field lines.
Hence, magnetic field line is a path along which a hypothetical free north pole 
tend to move towards south pole.
6. Characteristics of Magnetic field lines :
(1) The direction of magnetic field lines outside the magnet is always from 
north pole to south pole of bar magnet and are indicated by an arrow.
Inside the magnetic, the direction of field lines is from its south pole to north 
pole
Thus magnetic field lines are closed curve
(2) The strength of magnetic field is expressed by the closeness of magnetic 
field lines. Closer the lines, more will be the strength and farther the lines, less 
will be the magnetic field strength.
(3) No two field lines will intersect each other.
If they intersects, then at point of intersection the compass needle will show 
two direction of magnetic field which is not possible.
Tangent at the
point of intersection
shows two direction.
7. Magnetic field due to Current Carrying Conductor
+ –
(a)
x
N
S
y
Cu wire
+ –
(b)
x
N
S
y
Cu wire
The above electric circuit in which a copper is placed paralled to a compass 
needle, shows the deflection in needle gets reversed, when the direction of 
current reversed. Hence electricity and magnetism are related to each other.
8. Right Hand Thumb Rule :–
It is a convenient way of finding the direction of magnetic field associated 
with current carrying conductor.
Hold the straight were carrying current in your right hand such that thumb 
points towards the direction of current, then your folded fingers around the 
conductor will show the direction of magnetic field.
Direction of magnetic
field lines.
This rule is also called Maxwell’s corkscrew rule.
9. Magnetic Field due to Current through a Straight Conductor
A
+ –
+ –
Pheostat
Direction of
Current
Direction
of magnetic
field
Direction can be 
explained using 
Right Hand Thumb 
Rule
10. Magnetic Field due to Current through a circular Loop
+
–
Z S
X-Science
139
X-Science
140
Every point on the wire carrying current give rise to the magnetic field, 
appearing as a straight line at the centre of loop. By applying Right hand 
Thumb rule, we can find the direction of magnetic field at every section of the 
wire.
11. Solenoid– A Coil of many circular turns of insulated copper wire wrapped 
closely in the shape of a cylinder is called solenoid.
12. Magnetic field due to a current in a solenoid–
+ –
S N
– Using R.H. Thumb Rule, we can draw the pattern of magnetic field lives 
around a current carrying solenod.
– One end of the solenoid behaves as a magnetic north pole, white the other 
end behave as the South Pole.
– The filed lines inside the solenoid are in form of parallel straigh lines, that 
implies that magnetic field inside the solenoid is same at all points i.e. Field is 
uniform.
13. Electromagnet– Strong magnetic field inside the solenoid can be used to 
magnetise a magnetic material for example soft iron, when it is placed inside 
the coil. The magnet so formed is called electromagnet.
14. Force on a current carrying conductor in a magnetic field.
Andre Marie Ampere (1775-1836) suggested that the magnet also exert an 
equal and opposite force on the current carrying conductor.
+
–
N
S
rod
Iron Stand
Current Carrying
Aluminium rod should lie
between the two poles 
of magnet
Horse shoe magnet
Experiment®
Page 5


In this chapter, we will study the effects of electric current :
1. Hans Christian Oersted (1777-1851)
Oersted showed that electricity and magnetism are related to each other. His 
research later used in radio, television etc.
The unit of magnetic field strength is name Oersted in his honour.
2. Oersted Experiment
CHAPTER – 13
MAGNETIC EFFECTS OF 
ELECTRIC CURRENT
– +
Y
X
R K
XY is conductor (Cu wire)
through which current is passed
On passing the current through the copper wire XY in the circuit, the compass 
needle which is placed near the conductor gets deflected. If we reverse the 
direction of current, the compass needle deflect in reverse direction. If we 
stop the flow of current, the needle comes at rest.
Hence, it conclude that electricity and magnetism are linked to each other. It 
shows that whenever the current will flow through the conductor, then 
magnetic field around. it will developer
3. Magnetic Field – It is the region surrounding a magnet, in which force of 
magnet can be detected. It is a vector quantity, having both direction & 
magnitude.
4. Compass needle– It is a small bar magnet, whose north end is pointing 
towards north pole and south end is pointing towards south pole of earth.
5. Magnetic field lines–
When a bar magnet is placed on a card board and iron fillings are sprinkled, 
they will arrange themselves in a pattern as shown below.
X-Science
137
X-Science
138
N S
The lines along which the iron filling align themselves represent magnetic 
field lines.
Hence, magnetic field line is a path along which a hypothetical free north pole 
tend to move towards south pole.
6. Characteristics of Magnetic field lines :
(1) The direction of magnetic field lines outside the magnet is always from 
north pole to south pole of bar magnet and are indicated by an arrow.
Inside the magnetic, the direction of field lines is from its south pole to north 
pole
Thus magnetic field lines are closed curve
(2) The strength of magnetic field is expressed by the closeness of magnetic 
field lines. Closer the lines, more will be the strength and farther the lines, less 
will be the magnetic field strength.
(3) No two field lines will intersect each other.
If they intersects, then at point of intersection the compass needle will show 
two direction of magnetic field which is not possible.
Tangent at the
point of intersection
shows two direction.
7. Magnetic field due to Current Carrying Conductor
+ –
(a)
x
N
S
y
Cu wire
+ –
(b)
x
N
S
y
Cu wire
The above electric circuit in which a copper is placed paralled to a compass 
needle, shows the deflection in needle gets reversed, when the direction of 
current reversed. Hence electricity and magnetism are related to each other.
8. Right Hand Thumb Rule :–
It is a convenient way of finding the direction of magnetic field associated 
with current carrying conductor.
Hold the straight were carrying current in your right hand such that thumb 
points towards the direction of current, then your folded fingers around the 
conductor will show the direction of magnetic field.
Direction of magnetic
field lines.
This rule is also called Maxwell’s corkscrew rule.
9. Magnetic Field due to Current through a Straight Conductor
A
+ –
+ –
Pheostat
Direction of
Current
Direction
of magnetic
field
Direction can be 
explained using 
Right Hand Thumb 
Rule
10. Magnetic Field due to Current through a circular Loop
+
–
Z S
X-Science
139
X-Science
140
Every point on the wire carrying current give rise to the magnetic field, 
appearing as a straight line at the centre of loop. By applying Right hand 
Thumb rule, we can find the direction of magnetic field at every section of the 
wire.
11. Solenoid– A Coil of many circular turns of insulated copper wire wrapped 
closely in the shape of a cylinder is called solenoid.
12. Magnetic field due to a current in a solenoid–
+ –
S N
– Using R.H. Thumb Rule, we can draw the pattern of magnetic field lives 
around a current carrying solenod.
– One end of the solenoid behaves as a magnetic north pole, white the other 
end behave as the South Pole.
– The filed lines inside the solenoid are in form of parallel straigh lines, that 
implies that magnetic field inside the solenoid is same at all points i.e. Field is 
uniform.
13. Electromagnet– Strong magnetic field inside the solenoid can be used to 
magnetise a magnetic material for example soft iron, when it is placed inside 
the coil. The magnet so formed is called electromagnet.
14. Force on a current carrying conductor in a magnetic field.
Andre Marie Ampere (1775-1836) suggested that the magnet also exert an 
equal and opposite force on the current carrying conductor.
+
–
N
S
rod
Iron Stand
Current Carrying
Aluminium rod should lie
between the two poles 
of magnet
Horse shoe magnet
Experiment®
We will observe that the rod will displace i.e. the rod will experience a force, 
when it is placed in magnetic field, in a perpendicular direction to its length.
– The direction of the exert force will be reversed if the direction of current 
through the conductor is reversed.
– If we change the direction of field by inter changing the two poles of the 
magnet, again the direction of exert force will change.
– Therefore the direction of exerted force depends on
(1) direction of current
(2) direction of magnetic field lines.
15. Left Hand Fleming Rule
M  other F  ather C  hild
(Force) ® Motion Field Current
T  humb
Thrust (force)
Fore finger Middle finger
Three of them perpendicular to each other.
– According to this rule, stretch   thumb,     forefinger   and    middle finger 
of your    left hand    such that they are mutually    perpendicular   to each 
other.
If fore finger represent direction of magnetic field & middle finger 
represent direction of current, then thumb will point in the direction 
motion or force acting on the conductor.
– Functioning of   electric motor  is based on this rule. It convert electrical 
energy into mechanical energy.
16. Michael Faraday– Gave the law of Electro magnetic Induction
17. Galvanometer® It is an instrument that can detect the presence of a current 
in a circuit. If pointer is at zero (the centre of scale) the there will be no flow of 
current.
If the pointer deflect on either side right or left, this will show the direction of 
current. Represented by
o
G
X-Science
141