Paper 3 Nov 1999 Physics

Answer guide for O Level Physics (5054/3) – Paper 3 Practical Test November 1999

1(a) & (b)

l, w and ts all measured to the nearest mm with unit l 29.5 cm to 29.9 cm w 20.9 cm to 21.3 cm ts approximately 1 cm ts repeated at several points and t correct

(c)(i) (ii) (d)

m (4.80 g to 5.20 g) and V calculated correctly both with units Density calculated correctly with unit and 2 or 3 s.f. Reasonable assumption e.g. Single sheet of paper made from the same material as the stack Or dimensions of stack same as dimensions of single sheet or Sheets have same / uniform physical quantity e.g. mass / thickness / density / volume / area

2(a) (b)(i) & (ii) (c) (d)

(Setting up apparatus – no answer required) Inverted image made clear (adjusting appartus – no answer required) u and v measured to nearest mm with units and u > f (15.0 cm), v > u, and 95.0 cm _u + _v 105.0 cm (e)(i) & (ii) S found correctly by measuring across _ 3 gaps or 3 values for single space averaged (f)(i) & (ii) m and s calculated correctly with no units and correct units resp. Value of s 0.235 (cm) to 0.274 (cm)

3 (a) – (c) (d)(i) (d)(ii)

(e) (f)

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(setting up apparatus no answer required) At least two positions on each line clearly marked Two lines drawn correctly Precautions e.g. String held close to the lamina when positions marked or Lamina displaced to see whether it returns to the marked setting or Re-suspend after line marked and check line coincides with string p = 40 ± 2 mm Balance point X on a point e.g. finger, pencil, pin, etc or Check that X coincides with a third line from the other vertex of the triangle (seen or stated) or Suspend from X and see if it balances (or remains at rest) or Theoretical check of intersection of medians

© UCLES 2002

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Answer guide for O Level Physics (5054/3) – Paper 3 Practical Test November 1999

4(a) (b) (c) (d) (e) & (f)

(g)

(h)(i) (ii)

Power supply, ammeter, rheostat and heater in series Voltmeter in parallel with heater (Instruction to continue with experiment – no answer required) Readings Correct record of I and V with unit Correct calculation of P with unit Table with units including values of θ and t at 30 s intervals for 10 minutes

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Attempt at better than 1o C for at least one reading Points lie on a reasonably shaped curve Graph Axes labelled with units Suitable scale e.g. Allow origin provided graph fills half the page in either direction Scale must allow θi and temperature at 600 s to be plotted Allow a scale of 1 cm = 60 s on the time axis

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Two points plotted correctly Best fit smooth curve Calculations Reasonable tangent (accept any tangent close to θi )

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Large triangle and correct calculation (For a large triangle the hypotenuse of the triangle must occupy at least half the length of the tangent if it were produced to the edge of 1 the grid) (k)

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Correct substitution into equation with G in o C / s Correct calculation with unit and 2 or 3 s.f.

© UCLES 2002

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