9702_s10_qp_23
A paper of Physics, 9702
Questions:
7
Year:
2010
Paper:
2
Variant:
3
Login to start this paper & get access to powerful tools
1
A digital voltmeter with a three-digit display is used to measure the potential difference across a resistor. The manufacturers of the meter state that its accuracy is ±1% and ±1 digit. The reading on the voltmeter is 2.05 V. For this reading, calculate, to the nearest digit, a change of 1% in the voltmeter reading, change = V the maximum possible value of the potential difference across the resistor. maximum value = V The reading on the voltmeter has high precision. State and explain why the reading may not be accurate.
9. Electricity  →  9.2. Potential difference and power
10. D.C. circuits  →  10.3. Potential dividers
Open
2
For Examiner’s Use State the two conditions that must be satisfied for a body to be in equilibrium. 1. 2. Three co-planar forces act on a body that is in equilibrium. Describe how to draw a vector triangle to represent these forces. State how the triangle confirms that the forces are in equilibrium. For Examiner’s Use A weight of 7.0 N hangs vertically by two strings AB and AC, as shown in . B A 35° 50° 7.0 N C T2 T1 For the weight to be in equilibrium, the tension in string AB is T1 and in string AC it is T2. On , draw a vector triangle to determine the magnitudes of T1 and T2. T1 = N T2 = N By reference to , suggest why the weight could not be supported with the strings AB and AC both horizontal.
4. Forces, density and pressure  →  4.2. Equilibrium of forces
Open
3
For Examiner’s Use A cyclist is moving up a slope that has a constant gradient. The cyclist takes 8.0 s to climb the slope. The variation with time t of the speed v of the cyclist is shown in . v / m s–1 t / s Use to determine the total distance moved up the slope. distance = m For Examiner’s Use The bicycle and cyclist have a combined mass of 92 kg. The vertical height through which the cyclist moves is 1.3 m. For the movement of the bicycle and cyclist between t = 0 and t = 8.0 s, 1. use to calculate the change in kinetic energy, change = J 2. calculate the change in gravitational potential energy. change = J The cyclist pedals continuously so that the useful power delivered to the bicycle is 75 W. Calculate the useful work done by the cyclist climbing up the slope. work done = J For Examiner’s Use Some energy is used in overcoming frictional forces. Use your answers in to show that the total energy converted in overcoming frictional forces is approximately 670 J. Determine the average magnitude of the frictional forces. average force = N Suggest why the magnitude of the total resistive force would not be constant.
5. Work, energy and power  →  5.1. Energy conservation
16. Thermodynamics  →  16.2. The first law of thermodynamics
Open
4
For Examiner’s Use State the evidence for the assumption that there are significant forces of attraction between molecules in the solid state, the forces of attraction between molecules in a gas are negligible. Explain, on the basis of the kinetic model of gases, the pressure exerted by a gas. Liquid nitrogen has a density of 810 kg m–3. The density of nitrogen gas at room temperature and pressure is approximately 1.2 kg m–3. Suggest how these densities relate to the spacing of nitrogen molecules in the liquid and in the gaseous states.
15. Ideal gases  →  15.3. Kinetic theory of gases
4. Forces, density and pressure  →  4.3. Density and pressure
Open
5
For Examiner’s Use A source of sound has frequency f. Sound of wavelength λ is produced by the source. State 1. what is meant by the frequency of the source, 2. the distance moved, in terms of λ, by a wavefront during n oscillations of the source. distance = Use your answers in to deduce an expression for the speed v of the wave in terms of f and λ. The waveform of a sound wave produced on the screen of a cathode-ray oscilloscope (c.r.o.) is shown in . 1 cm 1 cm For Examiner’s Use The time-base setting of the c.r.o. is 2.0 ms cm–1. Determine the frequency of the sound wave. frequency = Hz A second sound wave has the same frequency as that calculated in . The amplitude of the two waves is the same but the phase difference between them is 90°. On , draw the waveform of this second wave.
7. Waves  →  7.1. Progressive waves
7. Waves  →  7.3. Doppler effect for sound waves
Open
6
For Examiner’s Use State what is meant by an electric current. Define electric potential difference. The variation with potential difference V of the current I in a component Y and in a resistor R are shown in . 0.4 0.5 0.6 0.7 0.3 I / A 0.2 0.1 V / V component Y component Y component Y resistor R For Examiner’s Use Use to explain how it can be deduced that resistor R has a constant resistance of 20 Ω. The component Y and the resistor R in are connected in parallel as shown in . E Y R 20 Ω A battery of e.m.f. E and negligible internal resistance is connected across the parallel combination. Use data from to determine the current in the battery for an e.m.f. E of 6.0 V, current = A the total resistance of the circuit for an e.m.f. of 8.0 V. resistance = Ω For Examiner’s Use The circuit of is now re-arranged as shown in . E Y R The current in the circuit is 0.20 A. Use to determine the e.m.f. E of the battery. E = V Calculate the total power dissipated in component Y and resistor R. power = W
9. Electricity  →  9.2. Potential difference and power
Open
7
For Examiner’s Use One property of α-particles is that they produce a high density of ionisation of air at atmospheric pressure. In this ionisation process, a neutral atom becomes an ion pair. The ion pair is a positively-charged particle and an electron. State what is meant by an α-particle, an approximate value for the range of α-particles in air at atmospheric pressure. range = cm The energy required to produce an ion pair in air at atmospheric pressure is 31 eV. An α-particle has an initial kinetic energy of 8.5 × 10–13 J. Show that 8.5 × 10–13 J is equivalent to 5.3 MeV. Calculate, to two significant figures, the number of ion pairs produced as the α-particle is stopped in air at atmospheric pressure. number = For Examiner’s Use Using your answer in , estimate the average number of ion pairs produced per unit length of the track of the α-particle as it is brought to rest in air. number per unit length =
11. Particle physics  →  11.1. Atoms, nuclei and radiation
24. Medical physics  →  24.3. PET scanning
Open