AS physics unit 3 revision notes (prt 1 - electricity experiments)

PHYSICS
EXPERIMENTS
(ELECTRICITY)




`In the matter of physics, the first lessons should contain
nothing but what is experimental and interesting to see. A
pretty experiment is in itself often more valuable than twenty
formulae extracted from our minds.' - Albert Einstein




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1

LEAVING CERTIFICATE PHYSICS
LISTED EXPERIMENTS
CONTENTS



ELECTRICITY

Verification of Joule's law (as I 2) ............................................................................ 4
To measure the resistivity of the material of a wire........................................................... 6
To investigate the variation of the resistance of a metallic conductor with temperature 8
To investigate the variation of the resistance of a…

Experiment at Higher Level only*
NOTE

For examination purposes any valid method will be acceptable for describing a particular
experiment unless the syllabus specifies a particular method in a given case.
Students will be expected to give details of equipment used, assembly of equipment, data
collection, data manipulation including graphs…

VERIFICATION OF JOULE'S LAW (As I 2)

Apparatus
Lagged beaker or calorimeter with a lid, heating coil, battery or low voltage power
supply, rheostat, ammeter or multimeter, thermometer, stopwatch, balance.




10°C
A



Lid
Digital
thermometer
Calorimeter Water


Heating coil Lagging




Procedure

1. Put sufficient water in a calorimeter to cover…

Results

1/°C 2/°C /°C I/A I 2/A2




A straight-line graph through the origin verifies that I 2 i.e. Joule's law.

Notes
Ensure that the rheostat current limit exceeds 3 A.

The heat energy produced is the mass multiplied by specific heat capacity multiplied by
rise in temperature: H = mc…

TO MEASURE THE RESISTIVITY OF THE MATERIAL OF A WIRE

Apparatus
Length of wire (nichrome, manganin), micrometer, ohmmeter, metre stick.



Nichrome
Crocodile clips
wire
Micrometer
l



Metre stick

Bench clamp Stand



Procedure

1. Note the resistance of the leads when the crocodile clips are connected together.
2. Tie a length…

Results

Micrometer Reading/mm




Resistance of leads =
Micrometer zero error =
Average of micrometer readings =
Diameter of wire =



R/ l/m R / m
/ m-1
l




Average value of =

Notes
Safety glasses should be worn as the wire could snap when stretched.

Use a micrometer with a…

TO INVESTIGATE THE VARIATION OF THE RESISTANCE OF A
METALLIC CONDUCTOR WITH TEMPERATURE

Apparatus
Coil of wire (see note), glycerol, beaker, heat source, thermometer, ohmmeter, boiling
tube.




10º C
10ºC





Digital
thermometer


Water Wire wound
on frame
Glycerol




Heat source




Procedure

1. Place the coil of wire in the boiling…

Results
R /
/ °C


Notes

The coil is commercially available. It is called the temperature co-efficient of resistance
apparatus with temperature apparatus.




9

TO INVESTIGATE THE VARIATION OF THE RESISTANCE OF A
THERMISTOR WITH TEMPERATURE

Apparatus
Thermistor, boiling tube containing glycerol or liquid paraffin, beaker, heat source,
thermometer, ohmmeter.



10°C Digital
thermometer








Water
Thermistor
Glycerol




Heat source

Procedure
1. Set up the apparatus as shown.
2. Connect the ohmmeter to the thermistor.
3.…