Mr gui eng hong
--- Good Luck for Your exams. !
Updated :
Disclaimer : Not all info. Here may be correct. Effort
has been made to ensure that they are as correct as possible.
Physics Practical Tips .
Rule # 1 : Do NOT start immediately. READ the instructions carefully.
Rule # 2 : If you really do not what to do (even if you are half-way thru), you may ask for help. Some marks may be deducted. But it is better than getting zero, if you anyhow do !
Rule # 3 : Change for spoilt equipment (low batt. , suspected bulb burnt , suspected Voltmeter spoilt ) ¨C NO penalty on candidates.
Science
Practical --
what to bring ?
¡¤ calculator (must be a approved model)
¡¤ transparent long ruler
¡¤ protractor
¡¤ compasses
¡¤ pencil & pen
¡¤ eraser
¡¤ flexi-rule
¡¤ i/c & entry proof
Science
Practical --
what NOT to bring ?
NO Mobile Phones or telecommunication devices allowed; not even in Reporting Room or Holding Room. Do NOT bring them to the school.
Check your shift and Reporting time. Your reporting time should be very early, compared to your actual commencement of paper. You must report on time .
Some pointers:
1.
Follow instructions on the examination paper
closely. Read and do them carefully, step
by step.
2.
If you are unable to proceed after 10-15 mins ,
ask for help. It is better to have 3-5 marks deducted than to score 0 out of 15
marks.
3.
Record your readings to the appropriate number of decimal
places, depending on the precision of the instrument.
4.
In calculations, leave your answer corrected to
3 significant figures.
5.
Remember to label your axis of the graph.
Example : voltage / v or current / amperes
6.
When asked to plot A vs B , A is on the vertical axis.
7. Show your workings on how you get the gradient from the graph.
8.
If no current flows in the circuit,
check that the connections are alright.
9.
The graph carries marks, plot it properly.
10. When asked to measure the distance between the lens and the image, measure from the centre of the lens, not the base of the holder of the lens.
1. Ask for a change of torch light if it is really weak.
2.
Clamp the torch light
at the same level as the lens¡¯s centre axis.
3.
Do not tilt the
lens.
4.
If not sure that
the image is the best focused, shift the XXX forward and backwards. If it is
the nbest focused image , then shifting forwards or backwards would result in a
poorer focused (blur) image. XXX can be the screen or lens or light source ,
depending on the question.
5.
When ask to see
image of pin in the mirror or beyond the glass block, made sure you are looking
into the mirror or through the glass block. Many pupils tend to look at the object
pin instead.
6. Refractive index = sin I / sin r , when I is the angle
of incidence of light from air into glass.
7. 2 Pins tracing a straight line should be as
far apart so as to reduce errors.
8. When balancing a ruler or rod, use your discretion
wisely. If you shift left , it topples one side, and if you shift right it
topples another side, then the point is the balancing point already. Otherwise,
continue shifting.
9. The balancing pivot (knife edge) should be touching
the ruler , not the jaws of the retort stand clamp.
10. Good girls , good boys, Good Luck ! remember to read instructions carefully.
Usually you are not
required in O level to set up the whole electrical circuit¡.. but if you
should,
11.
Use the voltmeter to check battery if you
suspect the battery is flat already.
12.
If the ammeter or voltmeter needle points
backwards (beyond the 0 point), the connections to the + and ¨C terminals may be
opposite. Try reversing them.
13.
Connect the electrical components that are in
series first. Then connect the electrical components in parallel.
14. Try to arrange the electrical components on your table at similar positions as drawn on the examination paper.
If the whole circuit is too messy and you are very confused, try to disconnect all and start again afresh.
Science Practical -- Where did all the 15 marks go to ?
4 Marks : Graph
4 Marks : Table
2 Marks : Calculations
5 Marks : General Questions
GRAPH ( 4 Marks)
1 mark
: both axis labelled correctly WITH units !!!
NB : V against L means V is plotted on the vertical axis !
1 mark
: points
plotted correctly (according to table of recordings) Examiner will check few
points .
1 mark
: BEST FIT line
The number of crosses above and below the line must more
all less be equal. Then we say the line is best fitted. It does NOT mean that
the best fit line must touch all points.
1 mark
: Choice of scale . If you choose a
weird scale like 7 squares is to 2cm, minus one mark. You must choose a scale
also to make sure that the graph is BIG.
At least half the graph paper. Reason : small
graph leads to higher errors.
Table of Recordings (4 Marks)
1 mark : Spread of values.
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L / cm |
Wrong ! |
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12.0 |
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13.5 |
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14.0 |
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15.0 |
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40.0 |
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L / cm |
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Right
! |
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18.0 |
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24.5 |
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32.0 |
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40.0 |
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1 mark : accuracy
1 mark : correct number of decimal point. (refer to table XYZ)
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V / Volts |
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Wrong ! |
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1 |
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1.60 |
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2.15 |
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3 |
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V / Volts |
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Right ! |
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1.00 |
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1.60 |
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2.15 |
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3.00 |
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1 Mark : correct heading wit units (e.g. L / cm) or correct calculations for
values (e.g. T 2 / s 2)
Average Values :
When asked
to determine an accurate value of say , diameter of
ball , or thickness of wood
Must take at least 3 readings. Show the examiner the three readings and the
working to find the average. !
Gradient ¡°triangle¡±
must be shown with dotted lines on graph .the triangle must be big (reduce
error)
How accurate should the recordings be done ?
¡¤
half the smallest division. (except for ruler and
protractor)
¡¤
Example
: voltmeter smallest division is 0.1 V. so recordings should be like 0.80 V,
0.85V , 1.20 V , 1.25 V ,1.30 V
|
Equipment |
Small
div. |
Recordings
up to . . . |
Examples |
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Ammeter |
0.02 A |
0.01 A |
0.22 A |
0.30 A |
0.83 A |
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Voltmeter |
0.1 V |
0.45 V |
1.35 V |
1.40 V |
1.45 V |
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Thermometer |
1 oC |
0.5 oC |
29.5 oC |
52.5 oC |
70.0 oC |
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Spring
Balance |
0.02 N |
0.01 N |
0.88 N |
0.89 N |
0.70 N |
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* Ruler |
0.1 cm |
0.1 cm |
12.2 cm |
67.0 cm |
6.0 cm |
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*
Protractor |
1 o |
1 o |
23 o |
40 o |
71 o |
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For PURE Physics Pupil :
For the
design question (last one) : do not give conclusion or
speculation . give the methods to further investigate.
Not speculating results !
9 68
20 285