A-level PHYSICS Paper 2 2 *02* IB/M/Jun22/7408/2

A-level PHYSICS Paper 2 2 *02* IB/M/Jun22/7408/2 Do not write outside the Section A box Answer all questions in this section. 0 1 Figure 1 shows an electric steam iron. Figure 1 Water from a reservoir drips ...

A-level PHYSICS Paper 2 2 *02* IB/M/Jun22/7408/2 Do not write outside the Section A box Answer all questions in this section. 0 1 Figure 1 shows an electric steam iron. Figure 1 Water from a reservoir drips onto an electrically-heated metal plate. The water boils and steam escapes through holes in the metal plate. The electrical power of the heater inside the iron is 2.1 kW. Assume that all the energy from the heater is transferred to the metal plate. 0 1 . 1 The metal plate has a mass of 1.2 kg and is initially at a temperature of 20 °C. The heater is switched on. After a time t the metal plate reaches its working temperature of 125 °C. Calculate t. specific heat capacity of the metal = 450 J kg−1 K−1 [2 marks] t = s Do not write outside the box 3 *03* Turn over ► IB/M/Jun22/7408/2 Do not write outside the 0 1 box . 2 The metal plate is maintained at its working temperature. Water at 20 °C drips continuously onto the metal plate. Steam at 100 °C emerges continuously from the iron. The maker claims that the iron can generate steam at a rate of 60 g min−1 . Determine whether this claim is true. specific latent heat of vaporisation of water = 2.3 × 106 J kg−1 specific heat capacity of water = 4200 J kg−1 K−1 [3 marks] 5 4 *04* IB/M/Jun22/7408/2 Do not write outside the 0 2 box . 1 In the kinetic theory model, it is assumed that there are many identical particles moving at random. State two other assumptions made in deriving the equation pV = 1 3 Nm (crms) 2 . [2 marks] 1 2 0 2 . 2 Explain why molecules of a gas exert a force on the walls of a container. Refer to Newton’s laws of motion in your answer. [3 marks] 5 *05* Turn over ► IB/M/Jun22/7408/2 Do not write outside the 0 2 box . 3 A sealed flask of volume 0.35 m3 contains an ideal gas at a pressure of 220 kPa. The mean kinetic energy of the gas molecules is 6.7 × 10−21 J. Calculate the amount of gas in the container. [3 marks] amount of gas = mol 0 2 . 4 Figure 2 shows the variation of pressure with volume for a fixed mass of an ideal gas at constant absolute temperature T. Draw, on Figure 2, the graph for the same gas at temperature 2T. [2 marks] Figure 2 10 6 *06* IB/M/Jun22/7408/2 Do not write outside the box 0 3 An isolated solid conducting sphere is initially uncharged. Electrons are then transferred to the sphere. 0 3 . 1 State and explain the location of the excess electrons. [2 marks] Figure 3 shows how the electric potential V varies with distance r from the centre of the sphere. The radius of the sphere is 0.10 m. Figure 3 7 *07* Turn over ► IB/M/Jun22/7408/2 Do not write outside the box 0 3 . 2 The magnitude of the electric field strength E is related to V by E = V r ∆ ∆ . Determine, using this relationship, the magnitude of the electric field strength at a distance 0.30 m from the centre of the sphere. State an appropriate SI unit for your answer. [4 marks] electric field strength = unit 0 3 . 3 The sphere acts as a capacitor because it stores charge at an electric potential. Show that the capacitance of the sphere is approximately 1 × 10−11 F. [3 marks] Question 3 continues on the next page 8 *08* IB/M/Jun22/7408/2 Do not write outside the 0 3 box . 4 Electrons leak away from the sphere with time and the amount of energy stored by the sphere decreases. At one instant, the magnitude of the electric potential of the sphere has fallen to 1.0 × 106 V. Calculate, for this instant, the change in the energy stored by the sphere. [3 marks] change in energy = J 12 9 *09* Turn over ► IB/M/Jun22/7408/2 Do not write outside the 0 4 box The lines in Figure 4 show the shape of the gravitational field around two stars G and H. Figure 4 0 4 . 1 Compare, with reference to Figure 4, the masses of G and H. [2 marks] 0 4 . 2 X and Y are two points in the field. Annotate Figure 4 to show the field direction at X and the field direction at Y. [1 mark] Question 4 continues on the next page 10 *10* IB/M/Jun22/7408/2 Do not write outside the 0 4 box . 3 A spherical asteroid P has a mass of 2.0 × 1020 kg. The gravitational field strength at its surface is 0.40 N kg−1 . Calculate the radius R of P. [1 mark] R = m 11 *11* Turn over ► IB/M/Jun22/7408/2 Do not write outside the 0 4 box . 4 Sketch, on Figure 5, the variation of the gravitational field strength g with distance r. The distance r is measured from the centre of P. [1 mark] Figure 5 0 4 . 5 Explain what is represented by the area under the graph between r = R and r = 2R on Figure 5.