aqa a level physics required practicals

equipment, method, diagram, information, risks, evaluations, graph, uncertainties of all the first 6 practical's required at AS level for teaching from September 2015

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Required practical's AQA ALevel Physics September 2015
Frequency of a stationary wave
Equipment
Signal generator
Vibration generator
Stand
2kg mass
1.5m length of string (eg 1.5mm thick)
Pulley which can be clamped to the bench
Wooden bridge slightly higher than the pulley
100g masses on a holder
Metre ruler
An electronic top pan balance with precision 0.1g or better
Method
1. Set up the apparatus as shown in the diagram.
2. Adjust the position of the bridge so that l is 1.000m measured using the metre ruler.
3. Increase the frequency of the signal generator from zero until the string resonates at its
fundamental frequency (as indicated in the diagram with a node at each end and a central
antinode).
4. Read the frequency f, on the signal generator dial.
5. Repeat the procedure with l = 0.900, 0.800, 0.700, 0.600 and 0.500m.
6. Obtain a second set of results by repeating the experiment and find the mean value of f
for each value of l.
7. Plot a graph of mean 1/f against l.
8. Draw the best straight line of fit though the points and find the gradient (the graph should
be a straight line through the origin).
9. The speed of the travelling waves on the string is c = f where is the wavelength.
When the string is vibrating in its fundamental mode, = 2l. Hence c = 2fl. The gradient
is 1/ fl so c is given by 2/gradient in ms1.
10. The speed is also given by c = (T/m) where T is the tension in the string in N and m is the
mass per unit length of the string in kgm1
11. With a 100g mass hanging from the string, T = 0.981N. m can be found by weighing the
1.5m length of string on an electronic balance, converting this into kg, and dividing by 1.5.
These values can then be substituted into the above equation to find another value for c,
which can be compared to the value obtained from the graph.
12. The experiment can be repeated with different masses hanging from the string, and
different thicknesses of string to investigate the effect of changing T and m.
13. Doubling the fundamental frequency while keeping l, T and m constant will cause the
string to resonate in its second harmonic (or first overtone, with nodes at either end, a
central node, and two antinodes). Tripling the frequency will give the third harmonic, and
so on

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Required practical's AQA ALevel Physics September 2015
Technical information
The signal generator should be operated for about 20 minutes in order for the frequency
to stabilise.
The power output (eg 20V peaktopeak) should be used. The output level should be
turned up to a value which gives steady vibrations of the vibration generator.
The string should be tied to the stand and passed through the hole in the vibration
generator.
The bridge should be at the same height as the hole.…read more

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Required practical's AQA ALevel Physics September 2015
Length 3.43m + 0.0005m
Tension 2.9439N + 0.…read more

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Required practical's AQA ALevel Physics September 2015
Young's double slit experiment
Equipment
laser ­ class II optical laser with output 1mW or less
darkened slight with double slit `rulings' (usually 1mm slit separation)
Vernier callipers to measure slit separation
Adjustable single slit (might be unnecessary with the laser)
white screen (wall covered with white paper may be suitable but paper must be matt
finish or nonreflective to reduce chances of reflected beams)
metre ruler
Method
1.…read more

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Required practical's AQA ALevel Physics September 2015
Risk assessment
Laser shining into eyes ­ turn off when not in use/don't point at people, reflection off screen ­ use
plain surface e.g. matt balck
Results analysis
As the distance increased, so did the slit separation
Wavelength found = 5.9x107
m, real wavelength of laser = 6.…read more

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Required practical's AQA ALevel Physics September 2015
Determination of g by freefall method
Equipment
Stand and clamp
Electromagnet
Low voltage variable DC supply (to power the electromagnet)
2kg mass
Steel ball bearing
Two light gates with bosses to attach them to the stand
An electronic clock or data logger with precision 1ms or better.
A pad (e.g. of felt) to protect the bench when the ball bearing lands.
Metre ruler
Method
1. Set up the apparatus as shown in the diagram.…read more

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Required practical's AQA ALevel Physics September 2015
Technical information
The electromagnet is a convenient way of releasing the ball bearing.
The low voltage supply should be set at the voltage specified by the manufacturer for the
electromagnet.
The supply is switched on and the ball bearing hung from the electromagnet. It will then
be released when the supply is switched off.
Several trials and adjustments will be required to ensure the ball bearing falls directly
through the light gates.…read more

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Required practical's AQA ALevel Physics September 2015
Counter 0.447sec + 0.…read more

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Required practical's AQA ALevel Physics September 2015
Young's modulus
Equipment
Ceiling beam or suitably strong fixing to attach loaded wires
2 x 1.5m lengths of copper wire
scale and Vernier arrangement with integral clamps for the wires
micrometer screw gauge
metre ruler
2 x slotted kg mass holders
selection of 0.5kg and 1kg slotted masses
safety goggles (in case wire breaks)
sand tray (to catch masses if wire breaks)
Method
1. Set up the apparatus as shown in the diagram.…read more

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