RI 2023 Physics Practical Revision Notes

1. 2. 3. 4. 5. 6. 7. Raffles Institution Physics Department Physics Practical Final Revision Notes General Information and Instructions Practical skills - important reminders Precision of Common Instruments Graphing skills Anomal y and Improvement discussions Planning question DMM settings Year 6 (2023) 1 Page 2 4 5 6 6 7 to 8 9 to 10

Raffles Institution Physics Department H2 Physics 97 49/ Paper 4 (Practical) The following revision notes apply to Prelim and A-Level Practical. Format of paper: Total duration Wei 2 hr 30 min A-Level format for reference : o 1 st hour : either 1 long or 2 short experiments o 2 nd hour: change over to the other experiment/s Marks 55 o Last½ hour: Planning question (cannot touch apparatus during this last 30 min or you will be penalised ! ) In 2021 : In 2022: The short questions were 01 [10 marks] and 02 [11 marks]. The long question was 03 [22 marks]. The planning question was 04 [12 marks]. The short questions were 01 [12 marks] and 02 [9 marks]. The long question was 03 [22 marks]. The planning question was 04 [12 marks]. Note that the number of experiments (long and short) for this year's A-Level may or may not be the same as previous years. What is definite is that the last ½ hour is set aside for 1 standard Planning question and you are not allowed to touch the apparatus during that time. (There may also be a short planning question as part of the hands-on experiment, besides the 30 min standard planning question.) Things to bring : 1. NRIC (or Foreign Identification document) . 2. Entry proof (for A-level). 3. Blue/black pen and sharp pencil, eraser. 4. 30 cm long plastic rule and Flex curve. 5. Mathematical set (including protractor, pair of compasses, set-square) . Remove the instruction sheet inside the mathematical set. 6. Calculator (with extra batteries) , extra calculator if possible (if using graphic calculator - learn how to clear memory!) . Check SEAS Website for approved calculators list. 7. Light snacks and drinks (may consume during holding periods for shifts 1 and 3). Water bottles must not be brought into the laboratories. 8. Revision notes (optional, to revise while in holding venue). 9. Sweater (optional, to be used in holding venue). Year 6 (2023) 2

' Things to note : Raffles Institution Physics Department 1. Handphones (or other communication devices, e.g. smart watches) must not be brought into holding venues and exam venues . Leave all valuables in the lockers before reporting for your attendance at the reporting venue. 2. Listen to instructions from invigilators - do not write or touch apparatus if no instructions are given (including writing of name). Do not continue to write when told that time is up (including writing of names, e.t.c. Request for permission first). This includes the change-over time, when a couple of minutes are given to check apparatus. You are not to do any writing during this period of time. 3. There should be no communication with friends , hand-shakes, "high-five" e.t.c., and do not borrow stationery, or ask friends to help clear memory of your graphic calculators. 4. Monitor the time, do not take too much time taking readings. 5. Scan through the whole question first and ensure you have taken readings for every part within the hour. After that you will not have access to the apparatus anymore and so it could mean you cannot complete your report. 6. If you suspect instruments are faulty, raise your hand and request for help. There will be no deduction of marks if the instruments are faulty. 7. If you are unable to proceed with the experiment, you may raise your hand and request for help. Assistance rendered will have to be reported and marks may, or may not, be deducted. However, this is better than not being able to get any readings to complete the report or submitting a blank report. 8. When you do ask for help with the set-up, be specific in your request so that you are not overly helped or under helped as all help must be reported which may have implications on your marks. For e.g. instead of saying 'I don't know what's wrong with my set-up', say 'I am not able to get any readings on my DMM' or 'I am unable to take readings because the plasticine keeps slipping off the wire'. 9. There may be an announcement of "The Examiners do not want you to waste time through inability to proceed with the experiment. Any candidate, who is unable to get on with the experiment after spending 15 minutes on it, may ask for help. The extent of this help will be reported to the Examiners, who may make a deduction of marks." Note that if you have difficulty, you do not need to wait for 15 minutes. You may request for help anytime. However do note that help rendered will be recorded and reported to the Examiners . 10. Your answer script is with you for the whole 2.5 hours . You may work on any of the questions at any time or start on the planning question if you have time during the first 2 hours (during the time you are allowed to write, refer to point 2 in this section). 11. Refra in from discussing the practical after it is over. Just be glad that you have done your best : ) Year 6 (2023) 3

Raffles Institution Physics Department Practical and Recording skills : Important Reminders 1. Practice tying of knots! 2. You are advised not to use correction fluid. Just cancel neatly and write again. 3. Record in blue/black ink for all readings and workings. 4. Use pencil for graph work and drawing of table outline (to record readings). 5. Uncertainty in a measurement : normally more than the least count of instrument, depending on the nature of the experiment. The uncertainty may also be estimated using tix = xmax - xm in . 2 Quote the larger value of the two approaches. Be mindful of the possible sources of uncertainty when doing the experiment. 6. % uncertainty : 1 or 2 s.f. 7. absolute uncertainty: 1 s.f. 8. s.f. : quote to least s.f. of raw data in calculations. Sometimes in the tabulation, you may add one more s.f. consistently in that column when the readings are too similar to one another. 9. Repeat readings - take multiple readings and find average for measurements that may not be uniform or cannot be measured precisely due to random errors (e.g. diameter of a wire, timing of oscillations e.t.c). If unsure, just repeat them without compromising the time to complete the experiment. 10. Number of oscillations for oscillatory experiments - the time for N oscillations should be at least 20 s. For cases when the oscillations die off before 20 s, repeat to obtain 3 sets of readings instead of 2 sets (without compromising the time to complete experiment). 11. Mass of mass hanger is usually 50 g - the value is normally printed on the hanger itself. 12. If vernier calipers or micrometer screw-gauge is used, state the value of the zero error ( even if it is zero), the reading from the instrument and the corrected value. 13. Column headings in the tabulation and recording of all quantities must include units. 14. For straight line, at least 6 readings. If non-linear: at least 8 readings (take more around turning point). 15. For tabulation of values, remember to include the first set of reading (which is taken prior to tabulation). 16. After calculation of constants, the values of the constants must include units (if any). 17. Analysis of graph (e.g. gradient and intercept) must be based on Best-fit line (BFL), and not on the plotted points (as plotted points may not lie on BFL). If point lies on BFL, the reading of that point should still be based on ½ smallest square precision and not on precision of tabulated value. Year 6 (2023) 4

Raffles Institution Physics Department Precision of common instruments (decimal places): Meter rule 1 d.p. in cm; 3 d.p. in m Vernier calipers for some models 2 d.p. in cm (or refer to precision printed on instr