9702_w10_qp_23
A paper of Physics, 9702
Questions:
9
Year:
2010
Paper:
2
Variant:
3
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4
For Examiner’s Use A student takes measurements to determine a value for the acceleration of free fall. Some of the apparatus used is illustrated in . electromagnet iron ball bench d The student measures the vertical distance d between the base of the electromagnet and the bench. The time t for an iron ball to fall from the electromagnet to the bench is also measured. Corresponding values of t2 and d are shown in . d /cm 0.02 0.04 0.06 0.08 0.10 0.12 t 2 / s2 0.14 For Examiner’s Use On , draw the line of best fit for the points. State and explain why there is a non-zero intercept on the graph of . Determine the student’s value for the diameter of the ball, diameter = cm the acceleration of free fall. acceleration = m s–2
2. Kinematics  →  2.1. Equations of motion
3. Dynamics  →  3.1. Momentum and Newton’s laws of motion
6. Deformation of solids  →  6.1. Stress and strain
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For Examiner’s Use A spring hangs vertically from a fixed point and a mass of 94 g is suspended from the spring, stretching the spring as shown in . mass 94 g 2.6 cm The mass is raised vertically so that the length of the spring is its unextended length. This is illustrated in . The mass is then released. The mass moves through a vertical distance of 2.6 cm before temporarily coming to rest. This position is illustrated in . State which diagram, , or , illustrates the position of the mass such that the mass has maximum gravitational potential energy, the spring has maximum strain energy. Briefly describe the variation of the kinetic energy of the mass as the mass falls from its highest position () to its lowest position (). For Examiner’s Use The strain energy E stored in the spring is given by the expression E = 1 2kx2 where k is the spring constant and x is the extension of the spring. For the mass moving between the positions shown in and , calculate the change in the gravitational potential energy of the mass, change = J determine the extension of the spring at which the strain energy is half its maximum value. extension = cm
6. Deformation of solids  →  6.1. Stress and strain
5. Work, energy and power  →  5.2. Gravitational potential energy and kinetic energy
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For Examiner’s Use State the principle of superposition. Coherent light of wavelength 590 nm is incident normally on a double slit, as shown in . screen P 2.6 m 1.4 mm A B coherent light wavelength 590 nm double slit (not to scale) The separation of the slits A and B is 1.4 mm. Interference fringes are observed on a screen placed parallel to the plane of the double slit. The distance between the screen and the double slit is 2.6 m. At point P on the screen, the path difference is zero for light arriving at P from the slits A and B. Determine the separation of bright fringes on the screen near to point P. separation = mm For Examiner’s Use The variation with time of the displacement x of the light wave arriving at point P on the screen from slit A and from slit B is shown in a and b respectively. x / arbitrary units –3 –2 –1 time wave from slit A a x / arbitrary units –2 –1 time wave from slit B b 1. State the phase difference between waves forming the dark fringe on the screen that is next to point P. phase difference = ° 2. Determine the ratio intensity of light at a bright fringe intensity of light at a dark fringe . ratio =
8. Superposition  →  8.3. Interference
8. Superposition  →  8.4. The diffraction grating
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For Examiner’s Use Two oppositely-charged parallel metal plates are situated in a vacuum, as shown in . negatively-charged metal plate positively-charged metal plate particle, mass m L charge + q speed v – + The plates have length L. The uniform electric field between the plates has magnitude E. The electric field outside the plates is zero. A positively-charged particle has mass m and charge +q. Before the particle reaches the region between the plates, it is travelling with speed v parallel to the plates. The particle passes between the plates and into the region beyond them. On , draw the path of the particle between the plates and beyond them. For the particle in the region between the plates, state expressions, in terms of E, m, q, v and L, as appropriate, for 1. the force F on the particle, 2. the time t for the particle to cross the region between the plates. For Examiner’s Use State the law of conservation of linear momentum. Use your answers in to state an expression for the change in momentum of the particle. Suggest and explain whether the law of conservation of linear momentum applies to the particle moving between the plates.
3. Dynamics  →  3.3. Linear momentum and its conservation
20. Magnetic fields  →  20.3. Force on a moving charge
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For Examiner’s Use An electric heater has a constant resistance and is rated as 1.20 kW, 230 V. The heater is connected to a 230 V supply by means of a cable that is 9.20 m long, as illustrated in . copper wires in cable 230 V 9.20 m heater, rated 1.20 kW 230 V The two copper wires that make up the cable each have a circular cross-section of diameter 0.900 mm. The resistivity of copper is 1.70 × 10–8 Ω m. Show that the resistance of the heater is 44.1 Ω, the total resistance of the cable is 0.492 Ω. For Examiner’s Use The current in the cable and heater is switched on. Determine, to three significant figures, the power dissipated in the heater. power = W Suggest two disadvantages of connecting the heater to the 230 V supply using a cable consisting of two thinner copper wires. 1. 2. Please turn over for Question 9.
9. Electricity  →  9.3. Resistance and resistivity
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