# experiment 4 10 ohms laws by E8S4V8u

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```									Experiment 10 - Electricity

Aim : To investigate whether a fixed resistor and a bulb obeys
Ohm’s Law

Apparatus : D.C. power supply, wire, variable resistor, switch,
ammeter , voltmeter, bulb, fixed resistor

Sources of error and precautions -

1.

2.

Method

The power supply was connected to a switch, variable resistor ,
ammeter and to the electric filament lamp in series. A voltmeter was
connected in parallel across the filament lamp. The variable resistor
was set up to maximum resistance so as to protect the ammeter. The
variable resistor was adjusted until the voltage across the lamp was
3.5 V. The current was read from the ammeter. The variable resistor
was adjusted so that the voltage decreased by 0.5 V. the current was
read once again. This was repeated until the voltage decreased to
zero. The data was recorded in table 1.

The filament lamp was replaced by a fixed resistor and the whole
procedure repeated. The data collected was recorded in table 2.
Results :

Table 1.      Voltage & current readings for a filament lamp.

V           0      0.5     1.0     1.5    2.0     2.5     3.0   3.5
Volts
I
amperes

Table 2.      Voltage & current readings for a fixed resistor.

V           0      0.5     1.0     1.5    2.0     2.5     3.0   3.5
Volts
I
amperes

A graph of current against voltage is drawn for each table.

Conclusion:

1. From this experiment it is observed that the ___________obeys
Ohm’s Law while the _______________ does not.

2. The straight line obtained by the ________________ shows that
the voltage is _____________to the current and so
obeys_______________.

3. At low currents the filament lamp ____________________but
as current rises, more ____________is produced. This produces
an increase in _____________, so the current value would be
__________ .

Discussion:

```
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