NJC_2024_H2_Physics_Prelim_P4_Ans

NJC Preliminary Examination 2024 H2 Physics Paper 4 Question Marking points Marks 1(a) Value of 𝑅𝐴 and 𝑅𝐵 recorded to nearest 0.1 Ω m-1. 1 1(b)(i) Values recorded to nearest 0.1 cm with correct unit (cm). 1 x > y. 1 1(c) Six sets of readings of x and y including the data from (a) without assistance. Correct trend of increasing x and y 1 Range: Smallest 20 cm ≤ x ≤ 30 cm and largest x ≥ 80 cm. 1 Each column heading (x, y, and ) contains a quantity and a unit. 1 All calculated values and must be given to the same number of significant figures as the raw values. 1 1(d) Axes: ● Sensible scales must be used, no awkward scales (e.g. 3:10 or fractions). ● Scales must be chosen so that the plotted points occupy at least half the graph grid in both x and y directions. ● Axes must be labelled with the quantity which is being plotted. ● Scale markings should be no more than two large squares apart. 1 Plotting of points: ● All observations in the table must be plotted on the grid. ● Diameter of plotted points must be ⩽ half a small square. ● Points must be plotted to an accuracy of half a small square in both the x and y directions. 1 Line of best fit: ● Judge by balance of all points on the grid about the candidate’s line (at least 6 points). There must be an even distribution of points either side of the line along the full length. ● Allow one anomalous point only if clearly indicated. There must be at least five points left after the anomalous point is disregarded. ● Lines must not be kinked or thicker than half a small square. 1 Gradient: ● The hypotenuse of the triangle used must be greater than half the length of the drawn line. ● Method of calculation must be correct, i.e. ∆y / ∆x. ● Gradient sign on answer line matches graph drawn. ● Both read-offs must be accurate to half a small square in both the x and y directions. 1 y-intercept: Check correct read-off from a point on the line and substituted into y = mx + c. Read-off must be accurate to half a small square in both x and y directions. or Intercept read directly from the graph at x = 0, accurate to half a small square. 1 Value of a = gradient with no unit. 1 Value of b = y-intercept with correct unit (cm–1 or m–1). 1 1(e) Correct calculation of Internal resistance r and r must be positive 1

2 Question Marking points Marks 2(b)(ii) Value of θ recorded to the nearest degree with correct unit. 1 L ≥ L0, expressed to 1 decimal place 1 2(c) Value of e calculated from L – L0. 1 Correct calculation of k. 1 2(d) m is varied to obtain angle θ, adjust the apparatus to keep the length of spring or extension of the spring fixed (and PQ horizontal) or m is varied to obtain extension of spring e, adjust the apparatus to keep θ fixed. 1 Plot a graph of cos 𝜃 against m or Plot a graph of e against m 1 State how k is calculated e.g. k = g / (cos 𝜃 × gradient) or k = g / (e × gradient) 1 Questio n Marking points Mark s 3(