Mark scheme for IGCSE Physics (0625/6) – Alternative to Practical November 1999
1 (a) 98, 83, 52 mm OR any other checkable value to ± 1 mm 1
corresponding values 68, 53, 21mm OR other checkable value to ± 1(mm) 1
Correct subtraction of candidate’s “Q” from candidate’s “P” (i.e. e.c.f) 1
Clear working throughout, accurate and in range (3/3.1) and good
presentation of h 1
(b) written answer / candidate’s diagram / from drawing on Fig 1.1:
ANY four points from:
Set perpendicular
zero on bench
close to tube
use of fiducial aid
position of eye to avoid parallax
read bottom of meniscus
use of background
repeats 4
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2 (a) Four acceptable symbols (i.e. can be found in text books) and in series 1
Power-supply polarity labelled, correct diode connection 1
Open switch 1
(b)(i) Polarity of ammeter compatible with diode connections 1
Ammeter anywhere in series with other components 1
(ii) Yes box ticked plus current is same at every point in circuit 1
(c)(i) 3/100 A, 0.03 A or 30mA (unit required) 1
(ii) no other resistance in circuit / 3 volt across 100 Ω / max resistance
is 100 Ω 1
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3 (a)(i) ratio of masses: 9 or 9:1, not other way round 1
ratio of areas: 8 - 8.1, or 8:1 etc 1
(ii) The height was the same for each area 1
“Use” of table, specific use or by just referring to areas, / balls / masses 1
Observation is consistent/true/same for all the masses or balls 1
(iii) as the mass decreases h increases 1
(b) Heaviest: each piece absorbs all of the KE / KE is transformed into other
forms of energy or into two other named forms / No KE of rebound 1 Lightest: each piece absorbs some KE/ some KE converted into other
forms etc / a “smaller” amount of KE of rebound 1
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4 (a)(i) reduce/prevent conduction of “heat” into (the solution) / insulates the can 1
(ii) produce a uniform temperature 1
(iii) assists in accurate temperature measurements 1
(b)(i) 18.7 or 18.8 0C 1
8.9 or 9 1
unit with one of the three temperatures 1
(ii) Any ONE point from
assists accuracy
helps avoiding parallax
more certain when the thread reaches the scale division 1
(c) Take the reading with the line of sight perpendicular to the scale,
marked on a diagram 1
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5 (a)(i) Correct axes {y against x) and labelled 1
Axes scaled sensibly occupying at least half the grid with units and using
the required origin 1
Five correct plots, to the nearest 1/3 small graph square 2
A fine line and neat plots 1
(b)(i) Five correct subtractions {2.3., 2.1, 2.3, 2.1, 2.1.} 1
Showing y – x on diagram 1
(ii) They remain constant / approximately constant 1
(iii) (y-x) larger 1
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