ASSESSMENT UNIT PH1: WAVES, LIGHT AND BASICS. P.M. THURSDAY, 21 May hours

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1 Candidate Name Centre Number Candidate Number GCE AS/A level 541/01 PHYSICS ASSESSMENT UNIT PH1: WAVES, LIGHT AND BASICS P.M. THURSDAY, 21 May hours ADDITIONAL MATERIALS In addition to this examination paper, you may require a calculator. INSTRUCTIONS TO CANDIDATES Write your name, centre number and candidate number in the spaces at the top of this page. Answer all questions. Write your answers in the spaces provided in this booklet. You are advised to spend not more than 45 minutes on questions 1 to 5. INFORMATION FOR CANDIDATES The total number of marks available for this paper is 90. The number of marks is given in brackets at the end of each question or part question. For Examiner s use Total You are reminded of the necessity for good English and orderly presentation in your answers. You are reminded to show all working. Credit is given for correct working even when the final answer given is incorrect. Your attention is drawn to the table of Mathematical Data and Relationships on the back page of this paper. SJJ*(S )

2 2 Fundamental Constants Avogadro constant N A = mol 1 Fundamental electronic charge e = C Mass of an electron m e = kg Mass of a proton m p = kg Molar gas constant R = 8 3 J mol 1 K 1 Acceleration due to gravity at sea level g = 9 8 m s 2 [Gravitational field strength at sea level g = 9 8 N kg 1 ] Universal constant of gravitation G = N m 2 kg 2 Planck constant h = J s Boltzmann constant k = J K 1 Unified mass unit 1 u = kg Speed of light in vacuo c = m s 1 Permittivity of free space εo = F m 1 Permeability of free space µ o = 4 π 10 7 H m 1 (541-01)

3 3 Examiner 1. (a) Define acceleration (b) (i) Two horizontal forces of 12 N and 8 N are applied to a toy car of mass 2 0 kg which is on a level surface. Calculate the maximum and minimum acceleration that could be experienced by the car. Sketch a free body diagram showing these forces when the car has minimum acceleration. (c) At a later time, the following condition applies to the toy car: F = 0 Complete the table below, indicating with a tick in one column, whether each of the statements given must be true, could be true or cannot be true when the above condition applies. [4] Statement Must be true Could be true Cannot be true The car is accelerating. The car is stationary. The car is moving at constant speed. There are no forces acting on the car (541-01) Turn over.

4 4 Examiner 2. Part of the graph of tensile stress against strain is plotted for an aluminium wire. stress/10 8 Nm strain / 10-3 (a) (i) Explain why strain has no units. Label clearly on the graph the limit of proportionality (iii) Explain briefly what is meant by inelastic (plastic) stretching, and circle the region of the graph corresponding to inelastic stretching. (b) (i) Calculate from the graph a value for the Young modulus of aluminium. Calculate the force needed to produce a strain of in an aluminum wire of cross-sectional area m 2. (541-01)

5 5 Examiner 3. (a) A student investigates the refraction of light in glass. She measures the angle of refraction for various angles of incidence for light passing from air into glass. She then plots a graph of Sine (angle of incidence) against Sine (angle of refraction). (i) Sketch, on the axes below, the graph that she might expect. Sine angle of incidence. Sine angle of refraction. State whose law this confirms. (b) The diagram shows a ray of light passing through a semicircular block of dense glass air (n = 1 00) (i) Determine the angle of incidence which would give an angle of refraction of 90. [4] What name is given to the angle calculated in (b) (i)? (iii) Calculate the radius of the glass block given that the time taken for the light to pass through it is 0 34 ns. [Refer to the data on page 2] (541-01) Turn over.

6 6 Examiner 4. Monochromatic (single wavelength) light is diffracted through a narrow single slit onto a distant screen. The diffraction pattern observed on the screen is shown below. Intensity of light Distance from centre (a) (b) On the graph axes sketch a graph of intensity of light against distance from centre for the above diffraction pattern. [4] The single slit is now placed directly in front of a double slit arrangement as shown. (The diagram is not to scale). Monochromatic (single wavelength) light source single slit double slit screen (i) Explain the purpose of the single slit in this arrangement. (541-01) Turn over.

7 7 Examiner A student wishes to produce a pattern of light and dark fringes of spacing 2 0 mm on the screen. He uses light of wavelength 5 9 x 10-7 m and the spacing between the double slits is 0 50 mm. Calculate the distance from the double slits to the screen. (iii) Explain briefly why the dark bands appear on the screen. (541-01) Turn over.

8 8 Examiner 5. High-sided lorries are vulnerable to cross-winds when crossing motorway bridges. The force, F, exerted by wind on the side of a lorry can be given by F = ρav 2 where ρ = density of air (kg m -3 ), A = side area of the lorry and v = speed of the wind. (a) (i) Show that the equation is correct in terms of units (or dimensions). The side of a certain lorry is (effectively) 15 0 m long and 4 2 m high. The force exerted on one side of the lorry by a cross-wind is N. Use this information to estimate the speed of the wind. (Density of air = 1 2 kg m -3 ). (b) When crossing a bridge, the lorry experiences a different cross-wind which causes it just to tilt as shown in the diagram. 2 8 m (i) G represents that point where the weight of the lorry is considered to act. Name this point Effective force of wind G 4 2 m If the lorry stays tilted as shown, the sum of the clockwise moments about the pivot must equal the sum of the anticlockwise moments about the same pivot. Clearly label the pivot on the diagram. (541-01)

9 9 Examiner (iii) Taking the force of the wind to act at a point midway up the side of the lorry, calculate the force needed to maintain the tilt as shown. The weight of the lorry is N and its width is 2 8 m. (541-01) Turn over.

10 10 Examiner 6. (a) (i) A stretched string can carry both progressive and stationary waves. State how the amplitude varies with position along the string for each of these waves. Progressive wave: Stationary wave: Explain how the energy flow for a progressive wave differs from that for a stationary wave. (b) Two points (P and Q) on a progressive wave differ in phase by 90. The distance between them is 0 30 m and their period of oscillation is s. P is shown on the following sketch. P (i) Label a possible position for Q on the above sketch. Define wavelength, and calculate its value for this wave. (541-01)

11 11 Examiner (iii) Calculate the speed of the wave. (iv) The amplitude of the wave is m. Calculate the mean speed of particle P over one complete cycle. (c) The following apparatus is set up to study stationary waves in a string of length 1 8 m. The vibration generator is set to 10 4 Hz initially in order to produce a stationary wave with three loops as shown. 1 8 m vibration generator (i) Label a node on the above sketch. Show on the diagram three points R, S and T that oscillate in phase. (iii) Calculate the speed of the wave. (iv) When the frequency of the vibration generator is doubled, the number of loops observed increases to six. Explain carefully how this change would affect, if at all, the speed of the wave. (541-01) Turn over.

12 12 Examiner 7. A passenger on a train, moving at a constant speed, drops a ball out of a window as shown. A stationary observer is standing near the track and directly in front of the window when the ball is dropped. (a) (i) If air resistance is neglected, describe and explain the horizontal motion of the ball as seen by the passenger. Describe the horizontal motion of the ball as seen by the observer. (b) If air resistance is now taken into account, how will your answers to (a) (i) and have to be modified? (541-01)

13 13 Examiner (c) The observer retrieves the ball and throws it vertically upwards, catching it on its return. A graph of height (from the observer s hand) against time is shown. 15 Height above observer s hand/m time/s (i) How can you tell from the graph that the air resistance now acting on the ball is negligible? Explain why the mean velocity of the ball during the flight is 0 ms -1. (iii) By considering the maximum height reached, determine the initial upward velocity of the ball. THE QUESTION CONTINUES ON THE NEXT PAGE (541-01) Turn over.

14 14 Examiner (iv) Use the answer to (c) (iii) and other data from the graph on the previous page to draw a velocity-time graph for the whole of the ball s flight. The time axis has been completed for you. [5] velocity /ms time/s (v) Use your velocity-time graph to verify the maximum height reached by the ball as shown on the height-time graph. (541-01)

15 15 Examiner (541-01) Turn over

16 16 Mathematical Data and Relationships SI multipliers Multiple Prefix Symbol Multiple Prefix Symbol atto a 10 2 centi c femto f 10 3 kilo k pico p 10 6 mega M nano n 10 9 giga G micro µ tera T milli m peta P Geometry and trigonometry P R θ Q PQ sin θ =, cos θ = QR PQ, tan θ =, sin θ = tan θ PR PR QR cos θ PR 2 = PQ 2 + QR 2 Areas and Volumes Area of a circle = π r 2 = π d 2 4 Area of a triangle = 1 2 base height Solid Surface area Volume rectangular block 2 ( lh + hb + lb ) lbh cylinder 2 π r ( r + h ) π r 2 h sphere 4 π r 2 4 π r 3 3 (541-01)

GCE AS/A level 1321/01 PHYSICS PH1 Motion Energy and Charge

Surname Other Names Centre Number 2 Candidate Number GCE AS/A level 1321/01 PHYSICS PH1 Motion Energy and Charge P.M. FRIDAY, 11 January 2013 1½ hours ADDITIONAL MATERIALS In addition to this examination