PAGS Flashcards
Measure the Speed of water ripples using a lamp.
How to measure wl, frequency, speed.
1) Use a signal generator to create water waves at a set frequency.
2) Use a lamp to see water crests on a screen below the tank.
Measure wl:
3) Measure the distance between 10 wave crests using a ruler.
4) Divide this by 10 to find av wl
5) Repeat 3 times.
-Measure frequency by counting the number of wave crests passing a fixed point over 10 s and divide the number by 10 to find the frequency.
Measure ws:
-mark out 2 fixed points on the screen and measure distance using a metre ruler between time and time how long it takes for one wavefront to travel this length: wave speed= distance/time.
Waves on a string PAG?
1) Fix a length of string to a signal generator with transducer. Turn it on and spring will start to vibrate.
2) Adjust freq of signal generator until a clear wave appears and freq will depend on the length of the string between the pulley and transducer and the masses.
3) Measure wl by measuring four or five wl in one go and divide to get mean wl. Doubt this to get a full wl.
4) Ws= frequency x wl.
Ways of reducing uncertainity in water waves PAG?
1) Use video camera to capture a picture.
2) Use a scale to measure the screen size and ripple tank size.
The motor makes a noise when it is turned on. Explain the difference between the properties of the sound waves produced by the motor and the water waves in the ripple tank (4 marks)
Sound waves are longitudinal and in long waves, the oscillations are parallel to the direction of energy transfer and water waves are transverse and in transverse was, the oscillations are perpendicular to the direction of energy transfer.
SHC experiment?
1) A block of material with two holes in it, one for the heater and thermometer.
2) Measure mass of block then wrap it in an insulating layer to reduce energy transferred. Insert the thermometer and heater.
3) Measure initial tempo of block and set pd at 10V. Turn on power supply and start stopwatch.
4) The current in the circuit does work on the heater, transferring energy electrically from power supply to heater’s thermal energy stores and the energy is then transferred to the material’s thermal energy stores by heating, causing material’s temp to rise.
5) As the block heats up, take readings of the temp and current ever min for 10 minutes. Current does not change.
6) Turn off power supply and using ur measured current and the pd, calculate the power P= VI.
Hooke’s Law Exp
1) Set up a ruler clamped to a stand that is straight- use a plumb line or set square.
2) Measure the orig length of the spring when no load is applied.
3) Add a mass to spring and allow it to come to a rest.
4) Record new length of spring- calculate extension by subtracting the original length.
5) Remove mass and check the spring has returned to orig length- repeat 3 times for each mass.
6) Repeat 3-5 steps for 6 different masses.
7) Calculate the force applied in Newtones= mass x gfc.
8) Calculate mean extension.
8) Plot a force- extension graph.
Inv Motion Pag
1) Set up trolley so it holds a piece of card with a gap in the middle that will the interrupt the signal on the light gate twice. Measure the length of each bit of card that will pass through the light gate and input this into the software, the light gate can measure the velocity of each bit of card- work out acceleration
2) Connect trolley to piece of string that goes over a pulley and is connected on the other side of the hook.
3) Weight of the hook and any masses attached to it will provide the accelerating force.
4) Weight of the hook and mass accelerate both the trolley and the masses- investigating the acceleration of the system.
5) Mark a starting line on the table of the trolley is on so trolley travels same distance.
6) Place trolley on starting line on the table, holding the string so its taut and release it.
7) Record acceleration measured by the light gate as the trolley passes through it and this acceleration is of the whole system.
8) Repeat twice to get average acceleration.
IV Characteristic PAG
1) Vary the variable resistor and see how that alters the current and the pd across the circuit
2) Take several readings of the ammeter and the voltmeter to see how the pd across the component varies as the current changes. Repeat each reading twice to get an average pd at each current.
3) Swap over the wire connected to the cell so the direction of current is reveresed.
4) PLot a graph of current against voltage.
How to use transparent materials to investigate refraction PAG?
1) PLace a transparent rectangular box on a piece of paper and trace around it. Use a ray box or a laser to shine a ray of light at the middle of one side of the box.
2) Trace the incident ray and mark where the light ray emerges on the other side of the box. Remove the block, and with a straight line, join up the incident ray and the emerging point to show the path of the refracted ray through the block.
3) Draw the normal at the point where the light ray entered the block and use a protractor to measure the angle between the incident ray and the normal and the angle of refraction- angle between the refracted ray and normal.
4) Repeat the experiment using rectangular locks made from diff materials, keeping the incident ray the same throughout.
Measuring how different material reflect light?
1) Take a piece of paper and draw a straight line through it. Place an object so one of its sides lines up with this line.
2) Shine a ray of light at the object’s surface and trace income and reflected light beams.
3) Draw the normal at the point where the ray hits the object and use a protractor to measure the angle of incidence and the angle of reflection- take note of the width and brightness of the reflected ray.
4) Repeat exp with a range of objects.
Why do systematic errors occur( 2 reason)
How to reduce systematic error?
- there is something wrong with the instrument or its data handling system, or
- because the instrument is wrongly used by the experimenter.
Reduce:
- take measurement several times.
- use a calliberated equipment
