Physics 9702/23 May/June 2021: question paper and mark scheme

Question

(a) A property of a vector quantity, that is not a property of a scalar quantity, is direction. For example, velocity has direction but speed does not. (i) State two other scalar quantities and two other vector quantities. scalar quantities: …… and …… vector quantities: …… and …… [2] (ii) State two properties that are possessed by both scalar and vector physical quantities. 1. …… 2. …… [2] (b) A ship at sea is travelling with a velocity of 13 m s–1 in a direction 35° east of north in still water, as shown in Fig. 1.1. N N velocity 13 m s–1 35° W E S Fig. 1.1 (i) Determine the magnitudes of the components of the velocity of the ship in the north and the east directions. north component of velocity = …… m s–1 east component of velocity = …… m s–1 [2] (ii) The ship now experiences a tidal current. The water in the sea moves with a velocity of 2.7 m s–1 to the west. Calculate the resultant velocity component of the ship in the east direction. resultant east component of velocity = …… m s–1 [1] (iii) Use your answers in (b)(i) and (b)(ii) to determine the magnitude of the resultant velocity of the ship. magnitude of resultant velocity = …… m s–1 [2] (iv) Use your answers in (b)(i) and (b)(ii) to determine the angle between north and the resultant velocity of the ship. angle = ……° [2] [Total: 11]

Question

(a) Define acceleration. …… [1] (b) A stone falls vertically from the top of a cliff. Fig. 2.1 shows the variation with time t of the velocity v of the stone. 40 v / m s–1 30 20 10 0 0 5 10 15 20 25 30 t/s Fig. 2.1 (i) Explain, with reference to forces acting on the stone, the shape of the curve in Fig. 2.1. …… [3] (ii) Use Fig. 2.1 to determine the speed of the stone when the resultant force on it is zero. speed = …… m s–1 [1] (iii) Use Fig. 2.1 to calculate the approximate height through which the stone falls between t = 0 and t = 30 s. height = …… m [3] (iv) On Fig. 2.2, sketch the variation with t of the acceleration a of the stone between t = 0 and t = 30 s. 20 a / m s–2 15 10 5 0 0 5 10 15 20 25 30 t/s Fig. 2.2 [3] [Total: 11]

Question

(a) Define the moment of a force about a point. …… [2] (b) Fig. 3.1 shows a type of balance that is used for measuring mass. fixed point P mm scale 200 spring 52.6 cm pan 1.8 cm pointer rod pivot 0 6.2 cm Fig. 3.1 (not to scale) A rigid rod is pivoted about a point 6.2 cm from the centre of a pan which is attached to one end. The object being measured is placed on the centre of this pan. A spring, attached to the rod 1.8 cm from the pivot, is attached at its other end to a fixed point P. The spring obeys Hooke’s law over the full range of operation of the balance. A pointer, on the other side of the pivot, is set against a millimetre scale which is a distance 52.6 cm from the pivot. When the system is in equilibrium with no mass on the pan, the rod is horizontal and the pointer indicates a reading on the scale of 86 mm. An object of mass 0.472 kg is now placed on the pan. As a result, the pointer moves to indicate a reading of 123 mm on the scale when the system is again in equilibrium. (i) Show that the increase in the length of the spring is approximately 1.3 mm. [2] (ii) Calculate the magnitude of the moment about the pivot of the weight of the object. moment = …… N m [2] (iii) Use your answer in (b)(ii) to determine the increase in the tension in the spring due to the 0.472 kg mass. increase in tension = …… N [2] (iv) Use the information in (b)(i) and your answer in (b)(iii) to determine the spring constant k of the spring. Give a unit with your answer. k = …… unit …… [2] [Total: 10]

Question

(a) State the principle of superposition. …… [2] (b) Two waves, with intensities I and 4I, superpose. The waves have the same frequency. Determine, in terms of I, the maximum possible intensity of the resulting wave. maximum intensity = …… I [2] (c) Coherent light of wavelength 550 nm is incident normally on a double slit of slit separation 0.35 mm. A series of bright and dark fringes forms on a screen placed a distance of 1.2 m from the double slit, as shown in Fig. 4.1. The screen is parallel to the double slit. screen 1.2 m light 0.35 mm wavelength 550 nm double slit Fig. 4.1 (not to scale) (i) Determine the distance between the centres of adjacent bright fringes on the screen. distance = …… m [3] (ii) The light of wavelength 550 nm is replaced with red light of a single frequency. State and explain the change, if any, in the distance between the centres of adjacent bright fringes. …… [1] [Total: 8]

Question

(a) Define the electromotive force (e.m.f.) of a source. …… [2] (b) The circuit shown in Fig. 5.1 contains a battery of e.m.f. E that has internal resistance r, a variable resistor, a voltmeter and an ammeter. E r X Y A V I Fig. 5.1 Readings from the two meters are taken for different settings of the variable resistor. The variation with current I of the potential difference (p.d.) V across the terminals XY of the battery is shown in Fig. 5.2. 8 V/V 6 4 2 0 0 0.2 0.4 0.6 0.8 1.0 1.2 I/A Fig. 5.2 Explain why V is not constant. …… [3] (c) For the battery in (b), use Fig. 5.2 to determine: (i) the e.m.f. E E = …… V [1] (ii) the maximum current that the battery can supply maximum current = …… A [1] (iii) the internal resistance r. r = …… Ω [2] (d) On Fig. 5.2, sketch a line to show a possible variation with I of V for a battery with a lower e.m.f. and a lower internal resistance than the battery in (b). Your line should extend over at least the same range of currents as the original line. [2] [Total: 11]

Question

(a) State the quark composition of: (i) a proton …… [1] (ii) a neutron …… [1] (iii) an alpha-particle. …… [2] (b) In the alpha-particle scattering experiment, alpha-particles were directed at a thin gold foil. State what may be inferred from: (i) the observation that most alpha-particles pass through the foil …… [1] (ii) the observation that some alpha-particles are scattered through angles greater than 90°. …… [2] (c) A proton and an alpha-particle are moving in the same uniform electric field. Determine the ratio acceleration of proton due to the electric field . acceleration of alpha-particle due to the electric field ratio = …… [2] [Total: 9]