NATIONAL SENIOR CERTIFICATE GRADE 12

Transcription

1 NTIONL SENIOR ERTIFITE GRE 1 PHYSIL SIENES: PHYSIS (P1) NOVEMER 011 MRKS: 150 TIME: 3 hours This question paper consists o 15 pages and 3 data sheets.

2 Physical Sciences/P1 E/November 011 INSTRUTIONS N INFORMTION 1. Write your centre number and examination number in the appropriate spaces on the NSWER OOK.. This question paper consists o TWO sections: SETION SETION (5) (15) nswer LL the questions in the NSWER OOK. You may use a non-programmable calculator. You may use appropriate mathematical instruments. Number the answers correctly according to the numbering system used in this question paper. YOU RE VISE TO USE THE TTHE T SHEETS. Give brie motivations, discussions, et cetera where required. Round o your inal numerical answers to a minimum o TWO decimal places.

3 Physical Sciences/P1 3 E/November 011 SETION QUESTION 1: ONE-WOR ITEMS Give ONE word/term or each o the ollowing descriptions. Write only the word/term next to the question number ( ) in the NSWER OOK The rate at which work is done The term that describes two sources that produce waves that have a constant phase relationship to each other The general name given to the insulating material between the plates o capacitors The type o current produced by an electric generator which has slip rings The unit o measurement o electric ield (1) (1) (1) (1) (1) [5] QUESTION : MULTIPLE-HOIE QUESTIONS Four options are provided as possible answers to the ollowing questions. Each question has only ONE correct answer. Write only the letter ( ) next to the question number (.1.10) in the NSWER OOK..1 Impulse is equal to the initial momentum o a body. inal momentum o a body. change in momentum o a body. rate o change in momentum o a body. (). n object is pulled along a straight horizontal road to the right without being lited. The orce diagram below shows all the orces acting on the object. N θ F w Which ONE o the above orces does POSITIVE WORK on the object? w N F ()

4 Physical Sciences/P1 4 E/November ball is released rom rest rom a certain height above the loor and bounces o the loor a number o times. The position-time graph below represents the motion o the bouncing ball rom the instant it is released rom rest. position (m) time (s) Neglecting air resistance, which point (,, or ) on the graph represents the position-time coordinates o the maximum height reached by the ball ater the SEON bounce? ().4 Water waves pass through a double slit. The resulting circular waveronts produced are shown as dotted and solid lines in the diagram below. Key: crests troughs barrier with double slit plane water waves Which ONE o the points (,, or ) lies on a nodal line? ()

5 Physical Sciences/P1 5 E/November The diagram below represents two pulses, each o amplitude a, travelling in opposite directions along a slinky coil. a a Which ONE o the ollowing represents the resultant amplitude at the instant that these two pulses meet? a a a ().6 set o identical light bulbs are connected as shown in the circuit diagrams below. The internal resistance o the battery is negligible. In which ONE o these circuits will the light bulbs glow the brightest? ()

6 Physical Sciences/P1 6 E/November The unit o measurement o THE RTE OF FLOW OF HRGE in a conductor is watt. volt. ampere. coulomb. ().8 Point P is a distance x rom the positive plate o a parallel-plate capacitor as shown in the diagram below x P The magnitude o the electric ield at P is E. t a distance 1 x rom the positive plate, the magnitude o the electric ield will be 1 E 4 1 E E E ().9 Which ONE o the ollowing descriptions best explains the ormation o a line emission spectrum? line emission spectrum is ormed when white light passes through a cold gas. white light passes through a triangular prism. electrons in the ground state move to a higher energy level. electrons in the excited state move to a lower energy level. ().10 Which ONE o the ollowing electromagnetic waves has the shortest wavelength? Radio waves Gamma rays Inrared rays Ultraviolet rays () [0] TOTL SETION : 5

7 Physical Sciences/P1 7 E/November 011 SETION INSTRUTIONS N INFORMTION Start EH question on a NEW page. Leave ONE line between two subquestions, or example between QUESTION 3.1 and QUESTION 3.. Show the ormulae and substitutions in LL calculations. Round o your inal numerical answers to a minimum o TWO decimal places. QUESTION 3 (Start on a new page.) hot-air balloon is moving vertically upwards at a constant speed. camera is accidentally dropped rom the balloon at a height o 9,4 m as shown in the diagram below. The camera strikes the ground ater 6 s. Ignore the eects o riction. v i 10 m P 3.1 t the instant the camera is dropped, it moves upwards. Give a reason or this observation. (1) 3. alculate the speed v i at which the balloon is rising when the camera is dropped. (4) 3.3 raw a sketch graph o velocity versus time or the entire motion o the camera. Indicate the ollowing on the graph: 9,4 m Initial velocity Time at which it reaches the ground (4) 3.4 I a jogger, 10 m away rom point P as shown in the above diagram and running at a constant speed o m s -1, sees the camera at the same instant it starts alling rom the balloon, will he be able to catch the camera beore it strikes the ground? Use a calculation to show how you arrived at the answer. (5) [14]

8 Physical Sciences/P1 8 E/November 011 QUESTION 4 (Start on a new page.) patrol car is moving on a straight horizontal road at a velocity o 10 m s -1 east. t the same time a thie in a car ahead o him is driving at a velocity o 40 m s -1 in the same direction. v PG = 10 m s -1 V PG =10 v TG = 40 m s -1 v PG : velocity o the patrol car relative to the ground v TG : velocity o the thie s car relative to the ground 4.1 Write down the velocity o the thie's car relative to the patrol car. () person in the patrol car ires a bullet at the thie's car. The bullet leaves the gun with an initial horizontal velocity o 100 m s -1 relative to the patrol car. Ignore the eects o riction. 4. Write down the initial velocity o the bullet relative to the thie's car. () While travelling at 40 m s -1, the thie's car o mass kg, collides head-on with a truck o mass kg moving at 0 m s -1. ter the collision, the car and the truck move together. Ignore the eects o riction. 40 m s -1 0 m s State the law o conservation o linear momentum in words. () 4.4 alculate the velocity o the thie's car immediately ater the collision. (6) 4.5 Research has shown that orces greater than N during collisions may cause atal injuries. The collision described above lasts or 0,5 s. etermine, by means o a calculation, whether the collision above could result in a atal injury. (5) [17]

9 Physical Sciences/P1 9 E/November 011 QUESTION 5 (Start on a new page.) rescue helicopter is stationary (hovers) above a soldier. The soldier o mass 80 kg is lited vertically upwards through a height o 0 m by a cable at a ONSTNT SPEE o 4 m s -1. The tension in the cable is 960 N. ssume that there is no sideways motion during the lit. ir riction is not to be ignored. 960 N 80 kg 5.1 State the work-energy theorem in words. () 5. raw a labelled ree-body diagram showing LL the orces acting on the soldier while being lited upwards. (3) 5.3 Write down the name o a non-contact orce that acts on the soldier during the upward lit. (1) 5.4 Use the WORK-ENERGY THEOREM to calculate the work done on the soldier by riction ater moving through the height o 0 m. (5) [11] QUESTION 6 (Start on a new page.) train approaches a station at a constant speed o 0 m s -1 with its whistle blowing at a requency o 458 Hz. n observer, standing on the platorm, hears a change in pitch as the train approaches him, passes him and moves away rom him. 6.1 Name the phenomenon that explains the change in pitch heard by the observer. (1) 6. alculate the requency o the sound that the observer hears while the train is approaching him. Use the speed o sound in air as 340 m s -1. (4) 6.3 How will the observed requency change as the train passes and moves away rom the observer? Write down only INRESES, ERESES or REMINS THE SME. (1) 6.4 How will the requency observed by the train driver compare to that o the sound waves emitted by the whistle? Write down only GRETER THN, EQUL TO or LESS THN. Give a reason or the answer. () [8]

10 Physical Sciences/P1 10 E/November 011 QUESTION 7 (Start on a new page.) learner investigates the change in broadness o the central bright band in a diraction pattern when light passes through single slits o dierent widths. She uses monochromatic violet light o wavelength 4 x 10-7 m. The apparatus is set up as shown in the diagram below. single slit screen monochromatic violet light a θ 7.1 eine the term monochromatic light. () 7. Write down the investigative question or this investigation. () 7.3 Write down TWO variables that are kept constant during this investigation. () 7.4 The learner now uses a narrower slit. How will the broadness o the central bright band change? Write down only INRESES, ERESES or REMINS THE SME. Give an explanation. () 7.5 alculate the angle θ at which the second minimum is ormed i a slit o width, x 10-6 m is used. (5) [13]

11 Physical Sciences/P1 11 E/November 011 QUESTION 8 (Start on a new page.) Two metal spheres, P and T, on insulated stands, carry charges o +3 x 10-9 and -6 x 10-9 respectively. +3 x 10-9 P T -6 x 10-9 The spheres are allowed to touch each other and are then placed 1,5 m apart as shown below. 1,5 m P T 8.1 In which direction will electrons low while spheres P and T are in contact? Write down only FROM P TO T or FROM T TO P. (1) 8. alculate the net charge gained or lost by sphere P ater the spheres have been in contact. (3) 8.3 alculate the number o electrons transerred during the process in QUESTION 8.. () 8.4 third sphere R, carrying a charge o -3 x 10-9, is NOW placed between P and T at a distance o 1 m rom T. alculate the net orce experienced by sphere R as a result o its interaction with P and T. (6) [1]

12 Physical Sciences/P1 1 E/November 011 QUESTION 9 (Start on a new page.) Learners conduct an investigation to veriy Ohm's law. They measure the current through a conducting wire or dierent potential dierences across its ends. The results obtained are shown in the graph below. 0,9 0,8 0,7 0,6 current () 0,5 0,4 0,3 0, 0,1 1,0 4,0 5, ,0,0 3,0 4,0 5,0 6,0 7,0 potential dierence (V) 9.1 Which ONE o the measured quantities is the dependent variable? (1) 9. The graph deviates rom Ohm's law at some point Write down the coordinates o the plotted point on the graph beyond which Ohm's law is not obeyed. () 9.. Give a possible reason or the deviation rom Ohm's law as shown in the graph. ssume that all measurements are correct. () 9.3 alculate the gradient o the graph or the section where Ohm's law is obeyed. Use this to calculate the resistance o the conducting wire. (4) [9]

13 Physical Sciences/P1 13 E/November 011 QUESTION 10 (Start on a new page.) The headlamp and two IENTIL tail lamps o a scooter are connected in parallel to a battery with unknown internal resistance as shown in the simpliied circuit diagram below. The headlamp has a resistance o,4 Ω and is controlled by switch S 1. The tail lamps are controlled by switch S. The resistance o the connecting wires may be ignored. The graph alongside shows the potential dierence across the terminals o the battery beore and ater switch S 1 is closed (whilst switch S is open). Switch S 1 is closed at time t 1. r V,4 Ω S 1 S potential dierence (volts) 1 9,6 0 t 1 time (s) tail lamp 1 tail lamp 10.1 Use the graph to determine the em o the battery. (1) 10. WITH ONLY SWITH S 1 LOSE, calculate the ollowing: urrent through the headlamp Internal resistance, r, o the battery (3) (3) 10.3 OTH SWITHES S 1 N S RE NOW LOSE. The battery delivers a current o 6 during this period. alculate the resistance o each tail lamp. (5) 10.4 How will the reading on the voltmeter be aected i the headlamp burns out? (oth switches S 1 and S are still closed.) Write down only INRESES, ERESES or REMINS THE SME. Give an explanation. (3) [15]

14 Physical Sciences/P1 14 E/November 011 QUESTION 11 (Start on a new page.) iesel-electric trains make use o electric motors as well as generators The table below compares a motor and a generator in terms o the type o energy conversion and the underlying principle on which each operates. omplete the table by writing down only the question number ( ) in the NSWER OOK and next to each number the answer. TYPE OF ENERGY ONVERSION PRINIPLE OF OPERTION Motor Generator (4) The simpliied diagram below represents an electric motor. N S 11. Give a reason why the section o the coil labelled in the above diagram does not experience a magnetic orce whilst the coil is in the position as shown. () 11.3 Graphs o the current and potential dierence outputs o an generator are shown below. current () t(s) t(s) -1 potential dierence (V) alculate the average power output o this generator. (6) [1]

15 Physical Sciences/P1 15 E/November 011 QUESTION 1 (Start on a new page.) metal surace is illuminated with ultraviolet light o wavelength 330 nm. Electrons are emitted rom the metal surace. The minimum amount o energy required to emit an electron rom the surace o this metal is 3,5 x J. ultraviolet light electrons metal 1.1 Name the phenomenon illustrated above. (1) 1. Give ONE word or term or the underlined sentence in the above paragraph. (1) 1.3 alculate the requency o the ultraviolet light. (4) 1.4 alculate the kinetic energy o a photoelectron emitted rom the surace o the metal when the ultraviolet light shines on it. (4) 1.5 The intensity o the ultraviolet light illuminating the metal is now increased. What eect will this change have on the ollowing: Kinetic energy o the emitted photoelectrons (Write down only INRESES, ERESES or REMINS THE SME.) Number o photoelectrons emitted per second (Write down only INRESES, ERESES or REMINS THE SME.) (1) (1) 1.6 Overexposure to sunlight causes damage to skin cells Which type o radiation in sunlight is said to be primarily responsible or this damage? Name the property o this radiation responsible or the damage. TOTL SETION : GRN TOTL: (1) (1) [14]

16 Physical Sciences/P1 1 E/November 011 T FOR PHYSIL SIENES GRE 1 PPER 1 (PHYSIS) GEGEWENS VIR FISIESE WETENSKPPE GR 1 VRESTEL 1 (FISIK) TLE 1: PHYSIL ONSTNTS/TEL 1: FISIESE KONSTNTES NME/NM SYMOL/SIMOOL VLUE/WRE cceleration due to gravity Swaartekragversnelling g 9,8 m s - Speed o light in a vacuum Spoed van lig in 'n vakuum c 3,0 x 10 8 m s -1 Planck's constant Planck se konstante h 6,63 x J s oulomb's constant oulomb se konstante k 9,0 x N m harge on electron Lading op elektron e -1,6 x Electron mass Elektronmassa m e 9,11 x kg Permittivity o ree space ε 0 Permittiwiteit van vry ruimte 8,85 x 10-1 F m -1

17 Physical Sciences/P1 E/November 011 TLE : FORMULE/TEL : FORMULES MOTION/EWEGING v v 1 = vi + a Δt Δx Δy = v iδt + aδt v i + v v i + v = vi + aδx or/o v = vi + aδy Δx = Δt or/o Δy = Δt FORE/KRG F net = ma p = mv F net Δt = Δp Δp = mv mv i 1 = v iδt + aδt or/o w = mg WORK, ENERGY N POWER/REI, ENERGIE EN RYWING W = FΔx cos θ U = mgh or/o E P = mgh 1 K = mv or/o E = k 1 mv W net = ΔK or/o Wnet = ΔEk Δ K = K K i or/o Δ Ek = Ek Eki W P = P= Fv Δ t WVES, SOUN N LIGHT/GOLWE, KLNK EN LIG v = λ v ± v v ± v = L L L = s or/o L b v ± v s v ± vb mλ sin θ = a 1 T = E= h E = h c λ E = W o + E k where/waar E = h and/en W 0 = h0 1 and/en E k = mv

18 Physical Sciences/P1 3 E/November 011 ELETROSTTIS/ELEKTROSTTIK kq Q 1 F= r V E = d kq1q = r Q = V U kq E = r F E = q W V = q = ε 0 d ELETRI IRUITS/ELEKTRIESE STROOMNE V R = I Rs = R1 + R = R R R p 1 W = Vq W = VI Δ t W= I R Δ t W= V Δt R em ( ε ) = I(R + r) emk ( ε ) = I(R + r) q = I Δ t W P = Δt P = VI P = I R V P = R LTERNTING URRENT/WISSELSTROOM Imax I rms = / Vmax Vrms = / I I = V wgk wgk = maks V maks P P I average = V rms rms / Pgemiddeld = V wgk wgk average I rms = R / P = R Vrms Paverage = / R P gemiddeld I wgk gemiddeld = V R I wgk