NATIONAL SENIOR CERTIFICATE GRADE 12

Transcription

1 NTIONL SENIOR ERTIFITE GRE 1 PHYSIL SIENES: PHYSIS (P1) FERURY/MRH 014 MRKS: 150 TIME: 3 hours This question paper consists of 15 pages and 3 data sheets.

2 Physical Sciences/P1 E/Feb. Mar. 014 INSTRUTIONS N INFORMTION 1. Write your centre number and examination number in the appropriate spaces on the NSWER OOK.. This question paper consists of 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 brief motivations, discussions, et cetera where required. Round off your final numerical answers to a minimum of TWO decimal places.

3 Physical Sciences/P1 3 E/Feb. Mar. 014 SETION QUESTION 1: ONE-WOR ITEMS Give ONE word/term for each of the following descriptions. Write only the word/term next to the question number ( ) in the NSWER OOK The sum of the kinetic energy and gravitational potential energy of an object The law of motion that can be used to explain why all persons in moving vehicles should wear safety belts The energy a charge possesses as a result of its position relative to other charges that it interacts with The bending of waves around corners or obstacles The minimum energy needed to remove an electron from the surface of a metal (1) (1) (1) (1) (1) [5] QUESTION : MULTIPLE-HOIE QUESTIONS Four options are given as possible answers to the following questions. Each question has only ONE correct answer. Write only the letter ( ) next to the question number (.1.10) in the NSWER OOK..1 Net force is a measure of the change in energy. rate of change in energy. change in momentum. rate of change in momentum. (). If air resistance is negligible, the total mechanical energy of a free-falling body remains constant. becomes zero. increases. decreases. ()

4 Physical Sciences/P1 4 E/Feb. Mar If the momentum of an object is doubled, then its kinetic energy is... halved. doubled. three times greater. four times greater. ().4 The degree of diffraction depends on a wave's... phase. velocity. amplitude. wavelength. ().5 The diagram below shows waves generated by two coherent sources, S 1 and S. The solid lines represent RESTS and the broken (dashed) lines represent TROUGHS. P Q R S S 1 S estructive interference occurs at points... Q and R. Q and P. Q and S. R and S. ()

5 Physical Sciences/P1 5 E/Feb. Mar Two small identical metal spheres, each carrying equal charges Q, are brought into contact and then separated. The charge on each sphere will now be zero. Q. Q. Q. ().7 Two resistors of equal resistance are connected in SERIES to a battery with negligible internal resistance. The current through the battery is I. When the two resistors are connected in PRLLEL to the same battery, the current through the battery will be ½I. I. I. 4I. ().8 Which ONE of the following statements is INORRET? Electromagnetic waves can undergo reflection and refraction. are longitudinal waves. can travel through a vacuum. can undergo diffraction and interference. ()

6 Physical Sciences/P1 6 E/Feb. Mar Which ONE of the following graphs represents the change in potential difference across a capacitor as it charges? potential difference (V) potential difference (V) time (s) time (s) potential difference (V) potential difference (V) time (s) time (s) ().10 Light spectra help to identify elements. White light is passed through a cold gas and then through a prism as shown in the sketch below. White light cold gas prism screen What type of spectrum is observed on the screen? Line absorption spectrum Line emission spectrum ontinuous absorption spectrum ontinuous emission spectrum () [0] TOTL SETION : 5

7 Physical Sciences/P1 7 E/Feb. Mar. 014 SETION INSTRUTIONS N INFORMTION Start EH question on a NEW page. Leave ONE line between two subquestions, for example between QUESTION 3.1 and QUESTION 3.. Show the formulae and substitutions in LL calculations. Round off your final numerical answers to a minimum of TWO decimal places. QUESTION 3 (Start on a new page.) stationary rocket on the ground is launched vertically upwards. fter 4 s, the rocket's fuel is used up and it is 5,6 m above the ground. t this instant the velocity of the rocket is 11,8 m s -1. The diagram below shows the path followed by the rocket. Ignore the effects of air friction. ssume that g does not change during the entire motion of the rocket. Q v = 11,8 m s -1 5,6 m P ground 3.1 Write down the direction of the acceleration of the rocket at point: P 3.1. Q (1) (1) 3. t which point (P or Q) is the rocket in free fall? Give a reason for the answer. () 3.3 TKING UPWR MOTION S POSITIVE, USE EQUTIONS OF MOTION to calculate the time taken from the moment the rocket is launched until it strikes the ground. (6) 3.4 Sketch a velocity versus time graph for the motion of the rocket from the moment it runs out of fuel until it strikes the ground. Take the time when the rocket runs out of fuel as t = 0 s. Indicate the following values on the graph: Velocity of the rocket when it runs out of fuel Time at which the rocket strikes the ground (5) [15]

8 Physical Sciences/P1 8 E/Feb. Mar. 014 QUESTION 4 (Start on a new page.) The momentum versus time graph of object, originally moving horizontally EST, is shown below. 100 Momentum (kg m s -1 ) time (s) Write down the definition of momentum in words. () 4. The net force acting on object is zero between t = 10 s and t = 0 s. Use the graph and a relevant equation to explain why this statement is TRUE. () 4.3 alculate the magnitude of the impulse that object experiences between t = 0 s and t = 50 s. (3) 4.4 t t = 50 s, object collides with another object,, which has a momentum of 70 kg m s -1 EST. Use the information from the graph and the relevant principle to calculate the momentum of object after the collision. (5) [1]

9 Physical Sciences/P1 9 E/Feb. Mar. 014 QUESTION 5 (Start on a new page.) loaded truck with a total mass of kg travels up a straight incline at a constant velocity of 15 m s -1. t the top of the incline, the truck is at a height of 55 m above its starting point. The work done by frictional forces is 8,5 x 10 4 J. (Ignore the rotational effects of the wheels of the truck.) kg 15 m s m 5.1 efine power in words. () 5. raw a labelled free-body diagram showing LL the forces acting on the truck as it moves up the incline. (4) 5.3 Use the WORK-ENERGY THEOREM to calculate the work done by the engine of the truck to get it to the top of the incline. (5) 5.4 alculate the average power delivered by the engine of the truck if the truck takes 60 s to reach the top of the incline. (3) The truck now returns down the same incline with a constant velocity of 15 m s m s kg 55 m 5.5 How will the work done by the engine of the truck on reaching the bottom of the incline compare to that calculated in QUESTION 5.3? Write down GRETER THN, SMLLER THN or EQUL TO. Give a reason for the answer. () [16]

10 Physical Sciences/P1 10 E/Feb. Mar. 014 QUESTION 6 (Start on a new page.) sound source on a car produces sound waves of frequency 850 Hz. stationary observer measures the emitted frequency using a detector which can measure a maximum frequency of 800 Hz. He finds that the detector only registers a reading whilst the car is moving. (Ignore the effects of wind.) 6.1 Must the car move TOWRS or WY from the observer for the detector to register a reading? Explain the answer by referring to frequency or wavelength. (3) 6. alculate the minimum speed at which the car must move for the detector to register the maximum reading. Take the speed of sound in air as 340 m s -1. (5) 6.3 State ONE use of the oppler effect in medicine. (1) [9]

11 Physical Sciences/P1 11 E/Feb. Mar. 014 QUESTION 7 (Start on a new page.) The diagram below shows monochromatic light that first passes through a single slit and then through a double slit. n interference pattern is observed on the screen. double slit single slit Monochromatic light S 1 S screen 7.1 What is the function of the double slit in the above arrangement? (1) 7. The width of the two slits S 1 and S and the distance between the slits are kept constant. How will the width of the bands in the interference pattern change if: (Write down only INRESES, ERESES or REMINS THE SME.) 7..1 Light of longer wavelength is used (1) 7.. Light of higher frequency is used (1) 7..3 The distance between the slits and screen is increased for a given frequency of light (1) The double slit is now removed and the light passes through the single slit only. 7.3 escribe the pattern that will be observed on the screen when the light passes through the single slit. () 7.4 When light of wavelength 450 nm passes through the single slit, the FOURTH minimum occurs at an angle of 5. alculate the width of the single slit. (5) One can hear sounds around the corners of a doorway, but cannot see around the corners. 7.5 Use your knowledge of diffraction to explain this observation. () [13]

12 Physical Sciences/P1 1 E/Feb. Mar. 014 QUESTION 8 (Start on a new page.) Three +100 μ point charges,, and, are equally spaced on a straight line in a vacuum. The charges are a distance of 3 cm from each other as shown in the sketch below μ 3 cm +100 μ +100 μ 3 cm 8.1 Name the law that describes the electrostatic force exerted by one point charge on another. (1) 8. learner sketches the electric field pattern produced by the three charges as shown below. Write down THREE mistakes the learner made. (3) 8.3 alculate the net electrostatic force experienced by point charge. (6) 8.4 Write down the net electrostatic force experienced by point charge. Give a reason for the answer. () [1]

13 Physical Sciences/P1 13 E/Feb. Mar. 014 QUESTION 9 (Start on a new page.) Two identical cells, EH with an emf of 1,5 V and an internal resistance r, are connected in series with each other and to the resistors as shown below. r r 4 Ω 1 Ω S V 9.1 efine, in words, the term electromotive force (emf). () 9. Write down the total emf of the circuit. (1) When switch S is closed, the potential difference across the 4 Ω resistor is,8 V. 9.3 alculate the total current in the circuit. (5) 9.4 alculate the internal resistance r of EH cell. (5) 9.5 n unknown resistor is now connected in parallel with the 4 Ω and 1 Ω resistors. How will this change affect the magnitude of: The internal resistance of the battery Write down only INRESES, ERESES or REMINS THE SME. (1) 9.5. The reading on the voltmeter Write down INRESES, ERESES or REMINS THE SME. Explain the answer by referring to resistance, current and 'lost volts'. (4) [18]

14 Physical Sciences/P1 14 E/Feb. Mar. 014 QUESTION 10 (Start on a new page.) 10.1 simplified diagram of an electric motor is shown below. N S Name the components labelled, and. Write down only the name of the component next to the letter ( ). (3) Write down the function of the component labelled. (1) Is this motor an motor or a motor? (1) Give a reason why component experiences a magnetic force when a current passes through it. () 10. coil is rotated in a magnetic field. The varying induced emf obtained is represented in the graph below. Potential difference (V) ,0 0,06 time (s) alculate the induced rms potential difference. (3) 10.. The coil is now rotated at TWIE the original speed. Write down the period of the new wave. () alculate the average power generated if the generator produces a maximum current of. (4) [16]

15 Physical Sciences/P1 15 E/Feb. Mar. 014 QUESTION 11 (Start on a new page.) 11.1 The apparatus below is used to demonstrate the photoelectric effect. incident light e - e - emitter collector potential difference efine, in words, the photoelectric effect. () The incident monochromatic light transfers 1,8 x 10-9 J of energy in one second to a certain area of the emitter. The wavelength of a photon in the incident light is 60 nm. If one photon releases one electron, calculate the: Number of electrons released from the surface of that area of the emitter in one second (5) urrent produced, in amperes (4) 11. The sketch below shows an example of a line emission spectrum riefly explain how this type of spectrum is formed by referring to electron transitions in atoms. () 11.. Write down ONE important use of line emission spectra. (1) [14] TOTL SETION : GRN TOTL:

16 Physical Sciences/P1 1 E/Feb. Mar. 014 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 of 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 of free space ε 0 Permittiwiteit van vry ruimte 8,85 x 10-1 F m -1

17 Physical Sciences/P1 E/Feb. Mar. 014 TLE : FORMULE/TEL : FORMULES MOTION/EWEGING vf v f 1 = vi + a t Δx Δy = v iδt + a t v i + v f v i + v f = v i + a x or/of v f = v i + a y Δx = Δt or/of Δy = Δt FORE/KRG F net = ma p = mv Fnet t = p p = mv mv f i 1 = v iδt + a t or/of w = mg WORK, ENERGY N POWER/REI, ENERGIE EN RYWING W = F x cos θ U = mgh or/of E P = mgh 1 1 W K = mv or/of E k = mv net = K or/of Wnet = Ek K = K f K i or/of Ek = Ekf Eki W P = P = Fv t WVES, SOUN N LIGHT/GOLWE, KLNK EN LIG v = f λ v ± v L L L = fs or/of L b v ± v s v ± v b f mλ sin θ = a f v ± v = f 1 T = f E = hf E = h c λ E = W o + E k where/waar E = hf and/en W 0 = hf0 1 and/en E k = mv

18 Physical Sciences/P1 3 E/Feb. Mar. 014 ELETROSTTIS/ELEKTROSTTIK kq Q r V E = d kq1q = r Q = V kq r F E = q W V = q 1 F= E = U = ε 0 d ELETRI IRUITS/ELEKTRIESE STROOMNE V R = I Rs = R1 + R = R R R p 1 W = Vq W = VI t W= I R t W= V Δt R emf ( ε ) = I(R + r) emk ( ε ) = I(R + r) q = I t W P = Δt P = VI P = I R V P = R LTERNTING URRENT/WISSELSTROOM Imax I rms = / I I = wgk maks V V = max rms / V Vwgk = maks P P average = V rms Irms / Pgemiddeld = V wgk I wgk average I rms = R / P = R Vrms Paverage = / R P gemiddeld I wgk gemiddeld = V wgk R