CIE A-level Physics Paper 3 Tips

Physics is a tough subject for me. I always have hard time with Physics. The only paper that can save me is probably Paper 3. Yea...maybe, I don't know.

So, I'm going to share a few tips of it.


First section
Basically, this section is all about table and graph.

For table:
-Make sure column of heading is correct.
-Each column heading must contain an appropriate unit.
-Significant figures of each column are correct.
-Values measured are in range.

For graph: 
-x-axis and y-axis have appropriate scale and labels.
-plots are correct and must the 'cross' must be smaller than the little box of the graph paper.
-line of best fit.
-good quality of the graph

After you have draw your graph, you can obtain gradient and y-intercept from it. Make sure you give an appropriate unit for your gradient and y-intercept.

For the last part of this section, they wil give you a related equation and will ask you to calculate the values of ___ and ___. Use the formula Y=mX+c to find the values.



Second section

If you see there are two mark boxes beside one measuring questions, measure it two times and find the average.

For the question, estimate the percentage uncertainty of x, use the formula,

(x1 -x2)/xavearage x 100

To justify the number of significant figure you have given for ___,
-___has __significant figure based on (eg. t and d)


To support the suggested relationship, you have to use the k values that you have calculated.
if k1<k2

(k2 - k1) / k1  x  100


Lastly, there will be source of uncertainty or limitation and the improvements that could be made in the experiment. I will list out a few general one. 

• 2 sets of measurement are not enough to draw a valid conclusion

         -repeat to obtain more measurements and plot a graph to obtain more k value

•   Time is too short when the object drops

         -Use a longer tube to increase the distance / take video with timer and replay to view it frame by            frame.

• x has to be taken at eye level on the point of release, but it is hard to determine the point of ___

         -Keep eyes parallel to the horizontal level of metre rule to predetermine the potential location of            x value.

• It is difficult to judge the centre of object 

        -Measure the tp and bottom of the object and calculate the average then mark the centre.

• Force of my finger to push object is different

        -Use a mechanical hand so that equal forces are exerted upon realease.

• Difficulty in deciding the toppling point of the object

       -Move by increment with newtonmeter and tilt until F=0

•  Difficulty to measure length of wire as the clips have width and I don't know where inside they grip the wire. 

      -Use a narrower clips.

• Difficulty to zero the newton-meter used when used horizontally.

      -Use a force sensor and computer.

• Voltmeter reading fluctuates because of contact resistance.

      -Clean the wires with wire wool first.

As long as your answers are logic and you write it in full, you can get the marks.