Question

Take an iron stand with a clamp.
Take a cotton thread of about 60
cm length. Tie it to the clamp so
that it hangs freely from it as shown
in Fig. 3.5. At the free end suspend
a pan so that weight can be placed
in it. Add weight one by one till the
thread breaks. Note down the total
weight required to break the thread.
This weight indicates the strength
of the fibre. Repeat the same activity
with threads of wool, polyester, silk
and nylon. Tabulate the data as
shown in Table 3.2. Arrange the
threads in order of their increasing
strength.
Observation Table 3.2
S. No. Type of Total Weight required
Thread/Fibre to break the Thread
1. Cotton
2. Wool
3. Silk
4. Nylon
You may use a hook or a nail on
the wall for hanging the fibres and
a polythene bag at the other end.
In place of weights you may
use marbles (or pebbles) of
similar size.
(Precaution : Note that all threads
should be of the same length and
almost of the same thickness.)

Answer 1

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The direction of magnetic field at the centre

of the circular loop depends on whether the

current in the loop flows in clockwise or

anticlockwise direction.When the current is in

clockwise direction, the magnetic field goes

into the side of wall.

when current is in clockwise direction the

direction of magnetic field (B) is towards

the circuit on the other hand when current

is in anticlockwise direction the direction of

magnetic field (B) is outwards the circuit.