Mark scheme for IGCSE Physics (0625/6) – Alternative to Practical November 2000
1
(a)(i)
(ii)
(iii)
(b)(i)
(ii)
(iii)
(iv)
use metre rule (or other straight edge) held horizontally
at height of rule near clamp
and measure height from floor
(OR measure height from floor near clamp 2)
(i.e. appreciation that even without weight, free end of rule is depressed)
metre rule and some means to ensure it is vertical (e.g. set-square)
means to more easily locate reading on vertical rule
(e.g. short rule, set-square)
OR fixing vertical rule in clamp & stand
OR convincing avoidance of parallax (action AND reason)
NOTE: (i), (ii) and (iii) may be scored directly from the diagram(s).
Take time (t) for several oscillations (N)
Calculate T from t/N
stopclock / stopwatch
make N as large as possible
OR repeat readings
use of fiducial mark at centre of oscillation
OR explanation of what fiducial mark means
OR shown on diagram
(mere use of word fiducial is not sufficient)
1
1
1
1
1
1
1
1
8
2
(a)
(b)
w / cm
x / cm
wx / cm2
w,x and wx tabulated
w and x with corresponding units
wx unit
correct wx value (2/3 sf) X3
all wx correct to + 2 mm
As x increases, w decreases
OR w decreases faster than x increases
4.4
3.30
14.5
2.8
5.90
16.5
1
1
1
1
1
2
1.9
7.75
14.7
0.95
10.65
10.1
7
3
(a)
need to add brass, not water, to cup
1
(b)
(start clock)
at stated time remove brass
place brass in cup after time t
1
1
(c)
(d)(i)
(OR hold thread, start clock at same time as removing brass
place brass in cup after time t)
cool for 60s
record maximum temperature of water
use fresh water from tap
1
1
1
(ii)
OR use thermometer to measure temperature and adjust
use 50 g – measure on balance
1
1
(e)
ensure temp same throughout liquid
1
8
4
(a)(i)
(ii)
r angle of resistance
to obtain any value of current
1
1
(b)(i) 1.
1
(ii)
2. move slider along line
1
3. to ensure good electrical contact
insulate 23 cm
correct end clear
OR
23cm
1
1
1
tape
7
5
(a)
graph:
(b)(i)
scales
labelled
plots correct to the nearest half square
line
y1 to the nearest half square
y2 to the nearest half square
ratios correct to 2/3 s.f.
force increases as separation decreases
x ratio is < 1; y ratio > 1
(ii)
2
1
1
2
1
1
1
1
1
1
10