LIMITATIONS AND IMPROVEMENTS FOR A LEVEL PHYSICS PAPER 3
The List of Common Answers for the
Limitations and Improvements Question of Paper 3 Question 2:
(a) Two/three readings are not enough to make a valid conclusion
- Take more readings and plot a graph
Note: This answer can be used for all
experiments
(b) The value of (a physical quantity) is small so the percentage uncertainty
of (the quantity) is large
- (The way to make the value of the quantity
larger)
(c) The movement/oscillation of (something) is affected by wind movement
- Use a wind shield when carrying out the
experiment
(d) Difficult to determine the start and end of oscillation/movement of
(something) because it moves too fast
- Use a video camera with slow motion feature
and timer to video the experiment with scale, then view the video playback frame
by frame.
(e) Difficult to release (something) without applying a force
- Use a mechanical hand to release the
(thing)
(f) Difficult to shape the plasticine into the shape of (something)
- Use a mould to shape the plasticine
(g) Heat loss through the sides and bottom of beaker/container
- Use polystyrene container or insulate the
beaker/container
Note: This answer should be used for
experiments involving the temperature of liquid.
(h) The (measuring instrument) is not precise enough
- Use another (instrument) with greater
sensitivity and precision
Note: You should state in
your answer the specific degree of precision for the limitation and the
improvement.
(i) The length/diameter/thickness of (something) is not uniform
- Measure the length around/along the (thing)
and calculate the mean
(j) Difficult to measure (something) due to (specific reason based on
experiment)
- (Suggest a better way to measure it)
(k) Parallax error when measuring (something)
- (Suggest a better way to measure it, such
as use mirror scale)
Note: This answer should only be used if the
measurement is difficult to make and parallax error is very likely to occur.
(l) (Something) moves
- (Way to keep it in the original position)
(m) Oscillation does not occur in one plane only
Note: No possible improvement for this
limitation. You should write in your answer the improvement for any other
limitation.
(n) Difficult to maintain (something) at (a particular position) / maintain
ruler vertical
- Use a clamp
(o) Difficult to zero the newton-meter when used horizontally
Note: No possible improvement for this
limitation. You should write in your answer the improvement for any other
limitation.
(p) Friction at pulley
- Apply oil to lubricate the pulley
(q) Resistance of contacts
- Clean the contacts
Note: This answer should be used for electric
experiments.
(r) Difficult to determine when (something) reach the maximum height because it
remains there for too short a time
(s) Difficult to take the reading of
newton-meter immediately when (something) starts to move
because it moves suddenly
(t) Difficult to start or stop the stopwatch
immediately when (something) passes through (somewhere)
- Use a video camera with slow motion feature
and (the measuring device) to video the experiment with scale, then view the
video playback frame by frame.
Note: The same improvement can be used for
limitations r, s and t.
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