Download 1. SL and HL This was often well answered. Some

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SL and HL
This was often well answered. Some candidates did not define momentum but instead
attempted to give a qualitative description. A significant number of candidates talked about
“lost” rather than “transformed” energy.
SL only
The definition of gravitational field strength was often incorrect.
[SL only] Circular motion
It was satisfying to see many correct answers to all parts of this question. The vectors in (a)
were correctly drawn and the calculation in (c) was complete. A few students lost a mark for
significant digits in (c).
SL and HL
It was common to find that candidates thought that the balance reading would be constant when
the water is boiling steadily. However, many did refer to either constant temperature or a steady
rate of production of bubbles. Very few candidates appreciated the reason for taking two
intervals instead of one. Many referred vaguely to it being “more accurate” without saying why.
It was pleasing to note that, when determining the gradient, very few used two points on the
line that were close together. Very few candidates were able to determine the specific latent
heat. Most answers did not include any factor to allow for the time of collection of the water.
There were some good responses but many referred to ‘errors in the meters’ or ‘energy losses in
the variable resistor’.
SL and HL
A significant number of candidates were unable to draw an appropriate straight line of
best fit for the points provided, though this did not cause any difficulty to the majority.
The most common mistakes were to attempt to draw the line without the aid of a ruler or
to join the 1st, 3rd and 5th points.
Surprisingly, many candidates failed to use the intercept and/or the gradient of the graph
in order to calculate required constants but instead they took data from two of the given
points and attempted to solve a pair of simultaneous equations. Whatever technique used,
many candidates made mistakes with the powers of ten and with units.
Very few candidates correctly suggested that the constant B should be zero; the most
common error was to suggest the value 8.3 having confused this with the universal molar
gas constant.
Many candidates managed to pick up marks by showing that they were correctly working
with the numbers that they had identified in parts (b) and (c). It was, however, common
to see candidates make errors involving powers of ten.
HL only
Only a handful of candidates attempted to approach this problem in an appropriate way.
It was disappointing to note that only a small minority were able to calculate the total
percentage error in any given reading of PV. These candidates were then often unable to
progress any further with the determination of absolute error in the calculated value of
the intercept.