Mark scheme for IGCSE Physics (0625/6) – Alternative to Practical November 2000
1(a)(i)use metre rule (or other straight edge) held horizontally
at height of rule near clamp1
and measure height from floor1
(OR measure height from floor near clamp 2)
(i.e. appreciation that even without weight, free end of rule is depressed)
(ii)metre rule and some means to ensure it is vertical (e.g. set-square) 1
(iii)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)1
NOTE: (i), (ii) and (iii) may be scored directly from the diagram(s).
(b)(i)Take time (t) for several oscillations (N)
Calculate T from t/N1
(ii)stopclock / stopwatch1
(iii)make N as large as possible
OR repeat readings1
(iv)use of fiducial mark at centre ofoscillation
OR explanation of what fiducial mark means
OR shown on diagram1
(mere use of word fiducial is not sufficient)
8
2(a)w,x and wx tabulated1
w and x with corresponding units1
wx unit1
correct wx value (2/3 sf) X31
all wx correct to + 2 mm1
(b)As x increases, w decreases
OR w decreases faster than x increases2
x / cm / 3.30 / 5.90 / 7.75 / 10.65
wx / cm2 / 14.5 / 16.5 / 14.7 / 10.1
7
3(a)need to add brass, not water, to cup1
(b)(start clock)
at stated time remove brass1
place brass in cup after time t1
(OR hold thread, start clock at same time as removing brass
place brass in cup after time t)
(c)cool for 60s1
record maximum temperature of water1
(d)(i) use fresh water from tap
OR use thermometer to measure temperature and adjust1
(ii) use 50 g – measure on balance1
(e)ensure temp same throughout liquid1
8
4(a)(i)r angle of resistance1
(ii)to obtain any value of current1
(b)(i) 1.
1
2. move slider along line1
3. to ensure good electrical contact1
(ii)insulate 23 cm1
correct end clear1
OR
23cm
tape
7
5(a) graph:
scales1
labelled1
plots correct to the nearest half square2
line1
(b)(i)y1 to the nearest half square1
y2 to the nearest half square1
ratios correct to 2/3 s.f.1
(ii)force increases as separation decreases1
x ratio is < 1; y ratio > 11
10
1