NCERT Book Class 10 Science Chapter 12 Magnetic Effects of Electric Current

CHAPTER 12
Magnetic Effects of
Electric Current

I n the previous Chapter on ‘Electricity’ we learnt about the heating
effects of electric current. What could be the other effects of electric
current? We know that an electric current-carrying wire behaves like a
magnet. Let us perform the following Activity to reinforce it.
Resistor
Activity 12.1
Long straight
conductor
n Take a straight thick copper wire and place it
between the points X and Y in an electric circuit,
as shown in Fig. 12.1. The wire XY is kept
perpendicular to the plane of paper.
n Horizontally place a small compass near to this
copper wire. See the position of its needle.
n Pass the current through the circuit by
inserting the key into the plug. Figure 12.1
n Observe the change in the position of the Compass needle is deflected on passing an electric
compass needle. current through a metallic conductor

We see that the needle is deflected. What does it mean? It means that
the electric current through the copper wire has produced a magnetic
effect. Thus we can say that electricity and magnetism are linked to each
other. Then, what about the reverse possibility of an electric effect of
moving magnets? In this Chapter we will study magnetic fields and such
electromagnetic effects. We shall also study about electromagnets which
involve the magnetic effect of electric current.

Hans Christian Oersted (1777–1851)

Hans Christian Oersted, one of the leading scientists of the 19th
century, played a crucial role in understanding electromagnetism. In
1820 he accidentally discovered that a compass needle got deflected
when an electric current passed through a metallic wire placed nearby.
Through this observation Oersted showed that electricity and
magnetism were related phenomena. His research later created
technologies such as the radio, television and fiber optics. The unit of
magnetic field strength is named the oersted in his honor.