SCGS 2025 Physics P3 MS

1 1 To investigate the force needed to pull a cylinder up a step. Qn Marking criteria Mark Remark 1(a) Evidence that more than one measurement is made and average calculated. Correct d.p. of measured/average value* 1 No mark awarded if BOTH criteria are not evident Mark awarded for correct d.p and with correct unit 1(b)(ii) Correct d.p. of measured value. 1 1(c) Evidence that more than one measurement is made and average calculated Radius r determined 1 No mark awarded if BOTH criteria are not evident Working optional 1(d)(i) Correct d.p. of measured value. 1 1(d)(ii) Angle  calculated. Working shown. 1 PLAN ▪ Independent, dependent variable ▪ one measurable controlled variable given ▪ Detail instructions on how the experiment is carried out to investigate relationship including instructions of how accurate results are achieved and instructions on tabulation and graph to be sketched. ▪ Explanation on how to reach conclusion from sketched graph. 1 1 2 1 Award mark for only for all three correct variables given Total 10 *all readings are expected to have the correct unit

2 Independent variable: mass, m Dependent variable: applied force, F Controlled variable: Height of string loop above the benchtop; loop parallel to ½ metre rule; newton meter parallel to benchtop. Procedure 1. Measure the mass each of the circular weight using the digital balance. Record the reading as m. 2. Take corresponding measurements for the diameter of the circular weight. Determine its radius r. 3. Measure the height h of the ½ metre rule using a vernier caliper. Determine the average height, have. 4. Set up the experiment as shown in Fig. 1.3 5. Pull the mass and ensure that the string is taut. 6. Measure the height of the string loop above the bench top. This height is to be measured and remain constant for every repeated measurement of the applied force. 7. View the string loop and the newton meter from the top. Ensure that both are aligned parallel to the benchtop. 8. Increase the applied force slowly until the mass is just about to roll up the edge of the ruler. Note the newton meter reading, F. 9. Repeat 4 to 8 to obtain another reading for F. Determine the average force applied, Fave. 10. Repeat steps (6) and (7) to obtain five other values of Fave . 11. Tabulate all readings. Convert the mass to kg. Include Reading m/kg F1/N F2/N Fave/N 1 2 3 4 5 12. Plot a graph of Fave against m. 13. Determine the gradient of the graph. 14. The equation is re-written as 𝑭 = 𝒌𝒎𝒈 𝐭𝐚𝐧 𝜶 where g = 10 N/kg is the acceleration due to gravity 15. A graph of Fave against m is expected to yield a straight line passing through the origin with gradient. 𝒌𝒈 𝒕𝒂𝒏 𝜶 Fave / N m /kg [5]

3 2 In this experiment you will determine the focal length of a semicircular block using two methods. Qn Marking criteria Mark Remark METHOD 1 2(a) R measured to correct d.p. 1 either ruler or digital caliper is used 2(b)(i) A and B measured to correct d.p. E = B/A calculated to correct s.f. 1 2(b)(ii) d1 measured to correct d.p. 1 2(b)(iii) d2 measured to correct d.p. 1 2(c) k determined to correct d.p. 1 d.p. determined by instrument used. 2(d) f calculated to correct s.f. 1 METHOD 2 2(e)(v)  recorded to correct 1o 1 2(f) 𝑛𝑔𝑙𝑎𝑠𝑠 calculated to correct sig.fig. Working shown 1 2(g) f calculated to correct sig.fig. Working shown 1 2(h) One improvement suggested 1 Total 10 *all readings are expected to have the correct unit

4 3 In this experiment you will investigate an electrical circuit. Qn Marking criteria Mark Remark 3(a) E recorded to correct d.p. 1 3(b) w and I1 recorded to correct d.p. 1 3(e) I2 recorded to correct d.p. 1 3(f) ▪ Table with quantities recorded using solidus notation with correct unit in headings ▪ 5 sets of readings of I1, I2 and w recorded ▪ 𝐼1 𝐼2 and 1 𝑤 calculated to correct sig.fig. ▪ Good range recorded ( 98 cm > w > 40 cm ) 1 1 1 1 e.c.f. for d.p. 3(g) ▪ Axes labeled with units and correct orientation (allow ecf from wrong unit in table). (A) ▪ Suitable scale; graph occupying ½ of graph paper. (S) ▪ All points plotted correctly. (P) ▪ Best fit line and fine crosses. (L) 1 1 1 1 -1 m for incorrect axis labelling 3(h) ▪ Triangle drawn that uses more than half the drawn line ▪ Coordinates (not points plotted) for determining gradient indicated on graph. ▪ Calculation of gradient shown to correct sig.fig. No unit. 1 1 Collective mark. Deduct if one condition not satisfied. 3(i) 1. Correct circuit diagram 2. Record of V and I to correct d.p. 3. Working shown clearly for the determination of RY. 1 2 2 3(j) Key source of error • The crocodile clip G is not clipped to the actual reading due to the large area of contact with the wire and this affects the accuracy of the value of w. • There may exist kinks in the wire and this affects the current flowing through the wire. 1

5 Qn Marking criteria Mark Remark (k) ▪ The equation is not valid for LDR and thermistors because the resistance of the resistors listed varies non-linearly with corresponding changes in environmental conditions e.g. light intensity, temperature. The graph of 𝐼1𝐼2 against 𝑅𝑉 will not be linear. ▪ The resistance of a wire is directly proportional to its length. The resistance of a thermistor is not directly proportional to its length. Hence graph of 𝐼1𝐼2 against 𝑅𝑉 will not be linear. ▪ The proposed theory will be valid (subject to further investigation) for the two variable resistors mentioned if the axes are changed to 𝑙𝑔(𝐼1𝐼2) [𝑦 𝑎𝑥𝑖𝑠] 𝑎𝑛𝑑 𝑙𝑔𝑆 [ x- axis]* 1 ∗ 𝑅𝑉 = 𝐾 𝑆𝑛 (a generalised inverse function to the power n) where K is a constant, S is the environmental conditions (temperature, light intensity) The equation 𝐼1𝐼2 = 𝐸2 𝑅𝑌 ( 1 𝑅𝑉 ) can be linearized to 𝑙𝑔(𝐼1𝐼2) = 2 lg 𝐸 − 𝑙𝑔𝑅𝑌+𝑙𝑔𝐾 − 𝑛𝑙𝑔𝑆 y = c + mc Total 20