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