EJC 2024 J2 H2 PRELIM Answers P4

©EJC 2024 9749/04/J2H2Prelim/2024 [Turn over EUNOIA JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS 2024 9749 PHYSICS MARK SCHEME Paper 4 – Practical Qns Answer Marks 1bi • Correct precision of 0.1 cm and corresponding unit for 1L • Repeated readings for 1L 1 • Correct precision of 0.1 cm and corresponding unit for 1x 1 1bii • Show ΔL0 < ΔL1 • Δx1 > 4 mm (ΔL0 < ΔL1) • Correct calculation of percentage uncertainty • 2 s.f. for final answer 1 no marks if not shown 1 1biii • Correct precision of 0.1 cm and corresponding unit for 2x • x2 > x1 1 1ci •  correctly calculated without units accept 2 or 3 s.f. 1 1cii Either • Plot a graph of 2x against 1x where the gradient is 2e and the y-intercept is zero. • ( ) = 1 ln gradient2 1 1 Or • Plot a graph of 2ln x against 1ln x where the gradient is 1 and the y-intercept is 2 • ( ) = 1 vertical intercept2 1ciii • If the pipe is frictionless, =12xx (as the spring will retract back to an extension of 1x after being stretched further). 1 • Hence, ( ) ( )==21ln ln 1 0xx and this implies  = 0 . 1 Total 10

2 ©EJC 2024 9749/04/J2H2Prelim/2024 Qns Answer Marks 2ai • Correct precision of 0.1 cm and corresponding unit for L and r • Repeated readings for L and r • Repeated readings for t in 2 d.p. • t > 10 s , 45.0 cm  L  55.0 cm • Correct calculation, number of d.p. / s.f. and unit for <t>, T 1 2aii • 1 cm ≤ ∆r ≤ 3 cm • Correct calculation of percentage uncertainty to 2 s.f. • Percentage uncertainty 10% 1 2b • 4 sets of readings without assistance • Correct trend: as L decreases, T decreases 1 • Correct column headings with correct units. Must include column for no. of oscillations & <t> • Repeated readings for t • Table must not be broken up into 2 separate tables 1 • Consistent and correct d.p. for raw data in each column • Correct s.f./d.p. for processed data • Correct calculation, s.f. for <t>, T • t > 10 s , 45.0 cm  L  55.0 cm 1 2c • Statement of graph to be plotted must be provided. • All observations must be plotted to an accuracy to half a small square. • Scale chosen is such that the plotted points occupy at least half the graph grid in both directions. Awkward scales (e.g. 1:3) are not allowed. • Axes are labelled no more than 4 cm apart, but no less than 2 cm apart • Best-fit line drawn 1 • Coordinates used to find gradient are read to the accuracy of half small square. • The coordinates used must be more than half the length of the line away. • Correct calculation of gradient to 3 s.f. 1 • A determined correctly with correct unit to 3 s.f. 1 2d • g determined correctly in m s−2 to 3 s.f. 1 2e • Percentage difference calculated correctly and given to 2 s.f. 1 • Compare percentage difference in g and percentage uncertainty in r • Draw correct conclusion depends on candidate’s experimental results. 1 2f • Expected line