2022 CHIJ Phy Prelims P3 Ans

2022 Sec 4E Physics Practical (6091/03) Question Answer Marks 1(a)(i) MMO Vo in the range 4.00 V to 5.00 V and to 2 decimal places with unit. [V] 1 1(a)(ii) MMO V1 < Vo and to the correct decimal place[2dp] with unit. [V] (allow ecf for dp and unit) I1 in the range 0.04 A to 0.12 A and to 2 decimal places with unit. [A] 1 1 1(a)(iii) ACE correct calculation of P1 to 2sf (or 3sf) with appropriate unit [W] 1 1(b)(i) MMO V2 < V1 and I2 > I1 1 1(b)(ii) ACE correct calculation of R with unit [Ω] 1 1(c) ACE correct calculation of Q with no units for proportion. 1 1(d) ACE • Set up apparatus as shown in Fig.1.4. • Move the boss upwards till the wooden rod cause the shaft to just stop moving. • Use a ruler to measure the extension of the spring. • Remove the string and the wooden rod. Place slotted mass on the spring till the same extension of the spring is obtained. • F = weight = mass x g 1 1 1(e) ACE Replace spring with a spring balance to measure the force directly OR Hang slotted mass on the shaft directly. 1

2 CHIJSec/2018/OLevelPrelim/6091/03 Question Answer Marks 2(a) MMO h measured to correct precision and unit. h = 5.1 cm 2(b) MMO Average of at least 2 sets of timing used to obtain to sensible to with units (~2.80s to 2 dp) 1 1 2(c) ACE correct calculation of average speed vo to 3sf with unit [cm/s] 1 2(d) ACE correct calculation of average speed v1 with unit [cm/s] distance = 50 cm used in calculation 1 2(e) ACE statement do not support the suggestion with evidence to support the statement. (value of vo ≠ v1) 1 2(f) P - identify correct variables to be kept constant [at least 2 different variables] ➔ distance travelled by the glass ball ➔ mass of glass ball ➔ surface of rule ➔ initial speed of glass ball / force used to release glass ball - Description of experiment ➔ Release the glass ball at the 1 cm mark on the metres rules and immediately start the stopwatch. Stop the stopwatch when the glass ball reaches the end of the track ➔ Repeat the above step again to obtain another set of reading and calculate the average time taken, tave. ➔ Calculate the average speed, v. (average speed = 99 / time) ➔ Record the values in a table. ➔ Keeping key variables constant, repeat experiment for 4 different height h to obtain the respective time taken. (at least 5 sets of readings) - Table with headings - Plot a graph of average speed, v against height, h . - Verify the relationship h / cm t1 / s t2 / s tave / s v / cms-1 2 1 1 1

3 CHIJSec/2018/OLevelPrelim/6091/03 Question Answer Marks 3(a)(i) ACE Place the light source, object, lens and screen in a straight line. Move the lens until a blurred image in seen on the screen. By moving the lens towards the screen or towards the object (back and forth) in small lengths, adjust the position until a sharp image is obtained 1 3(a)(ii) MMO us recorded to correct decimal place with appropriate unit us ~ 81.8 cm 1 3(b)(i) 3(b)(ii) MMO uL recorded to correct decimal place with appropriate unit uL ~ 18.3 cm ACE correct calculation of d with appropriate unit [cm] correct calculation of y with appropriate unit [cm2] 1 1 3(c) MMO at least 5 sets of data (D, us , uL, d and y) with correct trend. - us decreases as D decreases - uL increases as D decreases 4 PDO Table with quantities D, us , uL, d and y with appropriate units (allow ecf for units for y) MMO range of D of at least 40.0 cm (60.0 cm to 100.0 cm) PDO all values of D, us , uL, d and y given to the correct number of decimal places and significant figures. D (1 dp) us (1dp) uL (1dp) d (1dp) y (3sf) ACE Correct calculation for y 3(d) PDO axes labelled with units and correct orientation (allow ecf for wrong unit in table) 4 PDO suitable scale, not based on 3, 6, 7 etc with plotted data occupying more than half the page in both directions. PDO all points plotted correctly PDO best fit fine line and fine crosses 3(e)(i) ACE Gradient triangle seen that is bigger than half the best fit line and not using the data point 1 1 ACE correct calculation of gradient with working seen units [cm]

4 CHIJSec/2018/OLevelPrelim/6091/03 3(e)(ii) ACE correct calculation of f to (3sf) with appropriate units [cm] (Accuracy: 15 cm ± 10% = 13.5 cm to 16.5 cm) 1 3(f) ACE correct description of relationship based on graph drawn explain using of gradient of graph to support their description (y is linearly related to D. The gradient of the graph is constant and positive) 1 1 3(g) ACE - difficult to visually gauge the position where a clear image is obtained. There is a range of values of us and uL for which the image is focussed. This will affect the calculated value of d and y. - repeat the experiment a few times for the same value of D to identify the sharpest image. Find the average us and average uL. 1 1 3(h) ACE More than 2 times of focal length (> 2f) Answer more than their value of f (in 3(e)(ii)) multiplied by 2 with appropriate units [cm] 1