Page 597 - SUBSEC October 2017_Neat

PRACTICAL ACTIVITIES (cont’d)

Method: You will be provided with a set of 1% tolerance resistors and a high impedance
(digital) voltmeter. Design a suitable circuit and have the supervisor check it before
switching on.

Use the circuit to find the average time it takes for the p.d. to reduce to half its initial
value. Vary the value of R to obtain sufficient data to plot a suitable linear graph. Use
the graph to determine the given capacitance.

THE MAGNETIC FIELD LINES AROUND CURRENT CARRYING SOLENOID.

Refer to Unit 2 Module 1 Specific Objective 6.7

Objective:
To observe the magnetic field lines around current carrying solenoid.

Theory:

1. A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder
is called a solenoid.

2. The pattern of the magnetic field lines around a current-carrying solenoid is illustrated in Fig.1.

3. The pattern of the field is similar to magnetic field around a bar magnet. One end of the
solenoid behaves as a magnetic north pole, while the other behaves as the south pole.

4. The field lines inside the solenoid are in the form of parallel straight lines. This indicates that
the magnetic field is the same at all points inside the solenoid. That is, the field is uniform
inside the solenoid.

Apparatus:
A cardboard, a circular coil, a battery, a switch and iron filings.

Procedure:

1. Take a cardboard with two holes in it.

2. Pass a circular coil having large number of turns through these holes such that half the coil is
above it and the remaining part is below the cardboard.

3. Connect the free ends of the coil to a battery, and a switch in series.

4. Sprinkle iron filings on the cardboard and on the switch.

5. Tap the cardboard few times and observe the pattern of iron filings that is formed on
cardboard.

CXC A16/U2/17 97