DHS 2023 Prelim Physics (Paper 4 Solutions)

1 DHS H2 Physics Y6 Prelim Exam 2023 Paper 4 Mark Scheme Qn Marking Point Marks 1(b)(ii) I recorded to the nearest 0.1 mA and correct unit. 1 1(c) Quality of raw readings: 3 marks for 8 - 7 sensible readings (±5 𝑚𝐴) 2 marks for 6 - 5 sensible readings (±5 𝑚𝐴) 1 mark for 4 sensible readings (±5 𝑚𝐴) 0 mark for 3 or fewer readings R / Ω I / mA P / W 10 31.8 0.0101 20 28.4 0.0161 33 24.3 0.0195 43 21.7 0.0202 50 20.2 0.0204 60 18.4 0.0203 70 16.8 0.0198 100 13.4 0.0180 3 Correct calculation of P, to the correct significant figures (3 s.f.). 1 1(d) All observations must be plotted. Work to an accuracy of half a small square. 1 Correct shape (curve). 1 Best-fit curve drawn correctly - judge by scatter of points about the line drawn. There must be an even distribution of points on either side of the line. Line must not be kinked. 1 1(e) Value of R with unit read off correctly at maximum value of P. Acceptable range 40 to 60 Ω. 1 TOTAL MARKS FOR Q1: 9

2 Qn Marking Point Marks 2(a)(i) Value of M in the range 10.0 to 11.0 g with unit and to the correct decimal placing (3 d.p.). 1 2(a)(ii) Correct calculation of m dividing M by 25, with unit. 1 2(a)(iii) Justification for significant figures in m linked to the s.f. in M. (5 s.f.). 1 2(b)(i) Value of S in the range 1.0 – 2.0 g with consistent unit. 1 2(b)(ii) Correct calculation of c. 1 2(c)(i) Values of p and q such that p + q = 25 1 Evidence of repeated values of p. 1 2(c)(ii) Percentage uncertainty in p based on absolute uncertainty of 1 or 2, recorded to maximum of 2.s.f. 1 2(d) Quality: second value of q less than first value of q. 1 2(e)(i) Two values of k calculated correctly, and unitless. 1 2(e)(ii) Valid comment consistent with calculated values of k, testing against a criterion stated by the candidate.  Calculated correctly %kdifference = ∆k kave x 100% (1 Mark)  Chose a criterion from the value in 2(c)(ii). (1 Mark)  Concluded that results do not support the suggestion if % kdifference > the criterion chosen. OR Concluded results support the suggestion if %kdifference  the criterion chosen. 2 TOTAL MARKS FOR Q2: 12

3 Qn Marking Point Marks 3(b)(i) Value of l recorded with correct unit to nearest 1 mm. Range of l between 45.0 – 55.0 cm. Evidence of repeated readings. 1 3(b)(ii) Percentage uncertainty based on absolute uncertainty 0.2 ≥ l ≥ 0.5 cm recorded to maximum of 2.s.f. 1 3(c)(i) Value of t recorded with correct unit to 0.1 s. Evidence of repeated readings. 1 3(c)(ii) Percentage uncertainty based on absolute uncertainty 0.2 ≥ t ≥ 0.5 s recorded to maximum of 2.s.f. 1 3(d) Values of l, t recorded to correct d.p. and units. 1 Quality: second value of t is less than value in (c)(i). 1 3(e)(i) Two values of k calculated cor