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Tips for theory papers (Physics)

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Paper 1 Tips: Multiple Choice
• Attempt all questions – a mark is not deducted for a wrong answer.
• Use the space on the examination paper to write down clear working for each question. If you try to do
too much working solely on your calculator or in your head, you will make mistakes – many of the wrong
answers to a question can be reached by manipulating the data in a plausible, but incorrect, way.
• Carefully consider every one of the four possible answers before making your final decision as to which
one is correct – although you may initially think that the first or second option is the right answer you will
need to look at all four before the correct answer becomes clear.


Papers 2 and 4 Tips: Structured Questions
• If you are asked to sketch a diagram, this implies that a simple, freehand drawing is acceptable.
However, care should be taken over proportions and you should clearly show and label any important details
• If you are asked to sketch a graph, you should give as much information on your sketch as possible.
Label each axis with the appropriate quantity and unit. Then draw on the shape of the graph, ensuring
that it is correctly positioned relative to the axes and that the different parts of the graph line are in
proportion to each other. Don’t forget to put on your sketch graph the value of any applicable intercept,
asymptote, discontinuity or end point (if these are known).
• Memorise all definitions – you will need to be as precise as possible when quoting them in the
examination. Quantities are defined in terms of quantities. Units are defined in terms of units.
Remember to use “per” if a ratio is essential to the definition; for example, “pressure” should be
defined as “force per unit area” (not “force on unit area”).
• A non-numerical answer can sometimes be made clearer by adding a sketch, but remember to ensure
that it is clearly labelled and shows all the relevant information.
• Always give your answer to an appropriate number of significant figures. This can be judged from the
number of significant figures of the data given in the question.
• Occasionally a question will tell you the number of significant figures that are to be used in your answer
and in this case your answer must have exactly the number of significant figures specified.
• Do not prematurely round up figures at an intermediate stage during a calculation – wait until the answer
is reached and only then express it to an appropriate number of significant figures.
• When doing algebra ensure that the terms on either side of an “=” sign do in fact equal each other. It
is bad practice to write down a string of terms all on the same line and all connected by an “=” sign as
any error can result in the first element being of an entirely different nature and/or order to the last. This
often leads to errors when calculating the total resistance of a number of resistors connected in parallel.
• Any explanations that you give should be as clear and precise as possible. For example, saying “A
increases as B increases” would be insufficient if what is meant is “A is proportional to B"
• When substituting in the value of g use 9.81 m s–2 (not 10 m s–2).


Paper 3 tips: Practical test
• Do not panic if the context of the practical experiment appears unfamiliar. Where appropriate the
question paper will tell you exactly what to do and how to do it.
• If you find yourself in real difficulty setting up your practical equipment you may ask your supervisor for
help. You will only lose one or two marks for this.
• There are a number of things that you can do to save time: Draw a single table for your results in
advance of taking any readings and enter your readings in the table as you take them (so that you do
not waste time having to copy them up later). This is also important because you must record all your
raw readings before you calculate and record any average readings. If the number of readings that you
need to take is indicated in the question paper, do not waste time by exceeding this number. Repeat
your readings, but remember that it is only necessary to repeat them once (so that you have two sets of
values) – do not waste time repeating them more than once.
• All the raw readings of a particular quantity should be recorded to the same number of decimal places
which should in turn be consistent with the precision of the measuring instrument.
• The uncertainty in a measurement can sometimes be larger than the smallest interval that can be
measured by the measuring equipment. For example, a stopwatch can measure time to a hundredth of
a second, but human reaction times will mean that the uncertainty in the reading given by a stopwatch
is (typically) 0.1 s to 0.4 s.
• Each column heading in your table must contain both a quantity and its unit. For instance if you have
measured time t in seconds, your column heading would be written as “t/s” (“t in s” or “t(s)” would
also be acceptable). The quantity or unit or both may also be written in words rather than symbols.
• The number of significant figures used in a derived quantity that you calculate from your raw readings
should be equal in number to (or possibly one more than) the number of significant figures in the raw
readings. For example, if you measure potential difference and current to 2 and 3 significant figures
respectively, then the corresponding value of resistance calculated from them should be given to 2 or
3 significant figures, but not 1 or 4. If both were measured to 3 significant figures, then the resistance
could be given to 3 (or 4) significant figures.
• When drawing your graph, do not forget to label each axis with the appropriate quantity and unit, using
the same format for expressing column headings in a table. Choose a scale such that the plotted points
occupy at least half the graph grid in both the x and y directions. The x-axis scale should increase
positively to the right and the y-axis scale should increase positively upwards. Use a convenient scale
such as 1, 2 or 5 units to a 2 cm square as you will then be less likely to make a mistake with the
position of your plotted points and it will be easier for you to read off points from your graph if you are
calculating the gradient or finding an intercept. Similarly, it is good practice to mark values on at least
every other 2 cm square.
• All your plotted points should be on the grid; points in the white margin area will be ignored. Plot all your
observations and ensure that they are accurate to half a small square. A fine cross (or an encircled dot)
drawn with a sharp pencil is acceptable, but be careful not to obscure the position of your points by your
line of best fit or other working.
• When drawing your line of best fit, ensure you have an even balance of points about the line along its
whole length. If it is a straight line, use a clear plastic ruler so that you can see points on both sides of
the line as it is being drawn.
• Show all your working when calculating a gradient. It is helpful to draw the triangle used to calculate the
gradient on the graph and to clearly label the coordinates of the vertices (accurate to half a small square).
These values can then be used in the gradient calculation. The length of the hypotenuse of the triangle
should be greater than half the length of the graph line.
• If you are required to give a value for the y-intercept, it may be possible to directly read it off from your
graph from an axis where x=0. If this is not possible you can instead calculate the y-intercept by using
the equation of a straight line. In this case you should substitute into this equation a pair of x and y
values from your line of best fit along with your calculated value of gradient.
 
Last edited:
Messages
402
Reaction score
767
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I read it, and It's AH-mazing!! *w*
I'm sure I read the whole but can you tell me one thing? When I draw a graph in physics the ''dots'' are not in straight line, I heard that you can simply join any three points. is this correct? ._.
 
Messages
59
Reaction score
349
Points
63
I read it, and It's AH-mazing!! *w*
I'm sure I read the whole but can you tell me one thing? When I draw a graph in physics the ''dots'' are not in straight line, I heard that you can simply join any three points. is this correct? ._.
Which graph ?
 
Messages
34
Reaction score
138
Points
43
Paper 1 Tips: Multiple Choice
• Attempt all questions – a mark is not deducted for a wrong answer.
• Use the space on the examination paper to write down clear working for each question. If you try to do
too much working solely on your calculator or in your head, you will make mistakes – many of the wrong
answers to a question can be reached by manipulating the data in a plausible, but incorrect, way.
• Carefully consider every one of the four possible answers before making your final decision as to which
one is correct – although you may initially think that the first or second option is the right answer you will
need to look at all four before the correct answer becomes clear.


Papers 2 and 4 Tips: Structured Questions
• If you are asked to sketch a diagram, this implies that a simple, freehand drawing is acceptable.
However, care should be taken over proportions and you should clearly show and label any important details
• If you are asked to sketch a graph, you should give as much information on your sketch as possible.
Label each axis with the appropriate quantity and unit. Then draw on the shape of the graph, ensuring
that it is correctly positioned relative to the axes and that the different parts of the graph line are in
proportion to each other. Don’t forget to put on your sketch graph the value of any applicable intercept,
asymptote, discontinuity or end point (if these are known).
• Memorise all definitions – you will need to be as precise as possible when quoting them in the
examination. Quantities are defined in terms of quantities. Units are defined in terms of units.
Remember to use “per” if a ratio is essential to the definition; for example, “pressure” should be
defined as “force per unit area” (not “force on unit area”).
• A non-numerical answer can sometimes be made clearer by adding a sketch, but remember to ensure
that it is clearly labelled and shows all the relevant information.
• Always give your answer to an appropriate number of significant figures. This can be judged from the
number of significant figures of the data given in the question.
• Occasionally a question will tell you the number of significant figures that are to be used in your answer
and in this case your answer must have exactly the number of significant figures specified.
• Do not prematurely round up figures at an intermediate stage during a calculation – wait until the answer
is reached and only then express it to an appropriate number of significant figures.
• When doing algebra ensure that the terms on either side of an “=” sign do in fact equal each other. It
is bad practice to write down a string of terms all on the same line and all connected by an “=” sign as
any error can result in the first element being of an entirely different nature and/or order to the last. This
often leads to errors when calculating the total resistance of a number of resistors connected in parallel.
• Any explanations that you give should be as clear and precise as possible. For example, saying “A
increases as B increases” would be insufficient if what is meant is “A is proportional to B"
• When substituting in the value of g use 9.81 m s–2 (not 10 m s–2).


Paper 3 tips: Practical test
• Do not panic if the context of the practical experiment appears unfamiliar. Where appropriate the
question paper will tell you exactly what to do and how to do it.
• If you find yourself in real difficulty setting up your practical equipment you may ask your supervisor for
help. You will only lose one or two marks for this.
• There are a number of things that you can do to save time: Draw a single table for your results in
advance of taking any readings and enter your readings in the table as you take them (so that you do
not waste time having to copy them up later). This is also important because you must record all your
raw readings before you calculate and record any average readings. If the number of readings that you
need to take is indicated in the question paper, do not waste time by exceeding this number. Repeat
your readings, but remember that it is only necessary to repeat them once (so that you have two sets of
values) – do not waste time repeating them more than once.
• All the raw readings of a particular quantity should be recorded to the same number of decimal places
which should in turn be consistent with the precision of the measuring instrument.
• The uncertainty in a measurement can sometimes be larger than the smallest interval that can be
measured by the measuring equipment. For example, a stopwatch can measure time to a hundredth of
a second, but human reaction times will mean that the uncertainty in the reading given by a stopwatch
is (typically) 0.1 s to 0.4 s.
• Each column heading in your table must contain both a quantity and its unit. For instance if you have
measured time t in seconds, your column heading would be written as “t/s” (“t in s” or “t(s)” would
also be acceptable). The quantity or unit or both may also be written in words rather than symbols.
• The number of significant figures used in a derived quantity that you calculate from your raw readings
should be equal in number to (or possibly one more than) the number of significant figures in the raw
readings. For example, if you measure potential difference and current to 2 and 3 significant figures
respectively, then the corresponding value of resistance calculated from them should be given to 2 or
3 significant figures, but not 1 or 4. If both were measured to 3 significant figures, then the resistance
could be given to 3 (or 4) significant figures.
• When drawing your graph, do not forget to label each axis with the appropriate quantity and unit, using
the same format for expressing column headings in a table. Choose a scale such that the plotted points
occupy at least half the graph grid in both the x and y directions. The x-axis scale should increase
positively to the right and the y-axis scale should increase positively upwards. Use a convenient scale
such as 1, 2 or 5 units to a 2 cm square as you will then be less likely to make a mistake with the
position of your plotted points and it will be easier for you to read off points from your graph if you are
calculating the gradient or finding an intercept. Similarly, it is good practice to mark values on at least
every other 2 cm square.
• All your plotted points should be on the grid; points in the white margin area will be ignored. Plot all your
observations and ensure that they are accurate to half a small square. A fine cross (or an encircled dot)
drawn with a sharp pencil is acceptable, but be careful not to obscure the position of your points by your
line of best fit or other working.
• When drawing your line of best fit, ensure you have an even balance of points about the line along its
whole length. If it is a straight line, use a clear plastic ruler so that you can see points on both sides of
the line as it is being drawn.
• Show all your working when calculating a gradient. It is helpful to draw the triangle used to calculate the
gradient on the graph and to clearly label the coordinates of the vertices (accurate to half a small square).
These values can then be used in the gradient calculation. The length of the hypotenuse of the triangle
should be greater than half the length of the graph line.
• If you are required to give a value for the y-intercept, it may be possible to directly read it off from your
graph from an axis where x=0. If this is not possible you can instead calculate the y-intercept by using
the equation of a straight line. In this case you should substitute into this equation a pair of x and y
values from your line of best fit along with your calculated value of gradient.
Nice work (y)
 
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