9702_w06_qp_4
A paper of Physics, 9702
Questions:
8
Year:
2006
Paper:
4
Variant:
0
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2
A mercury-in-glass thermometer is to be used to measure the temperature of some oil. The oil has mass 32.0 g and specific heat capacity 1.40 J g–1K–1. The actual temperature of the oil is 54.0 °C. The bulb of the thermometer has mass 12.0 g and an average specific heat capacity of 0.180 J g–1K–1. Before immersing the bulb in the oil, the thermometer reads 19.0 °C. The thermometer bulb is placed in the oil and the steady reading on the thermometer is taken. Determine the steady temperature recorded on the thermometer, temperature = ………………………… °C [T the ratio change in temperature of oil . initial temperature of oil ratio = ………………………… Suggest, with an explanation, a type of thermometer that would be likely to give a smaller value for the ratio calculated in . The mercury-in-glass thermometer is used to measure the boiling point of a liquid. Suggest why the measured value of the boiling point will not be affected by the thermal energy absorbed by the thermometer bulb. Examiner s Use
14. Temperature  →  14.3. Specific heat capacity and specific latent heat
14. Temperature  →  14.2. Temperature scales
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3
Two vertical springs, each having spring constant k, support a mass. The lower spring is attached to an oscillator as shown in . The oscillator is switched off. The mass is displaced vertically and then released so that it vibrates. During these vibrations, the springs are always extended. The vertical acceleration a of the mass m is given by the expression ma = –2kx, where x is the vertical displacement of the mass from its equilibrium position. Show that, for a mass of 240 g and springs with spring constant 3.0 N cm–1, the frequency of vibration of the mass is approximately 8 Hz. Use mass oscillator [T The oscillator is switched on and the frequency f of vibration is gradually increased. The amplitude of vibration of the oscillator is constant. shows the variation with f of the amplitude A of vibration of the mass. State the name of the phenomenon illustrated in , the frequency f0 at which maximum amplitude occurs. frequency = ………………………… Hz Suggest and explain how the apparatus in could be modified to make the peak on flatter, without significantly changing the frequency f0 at which the peak occurs. Examiner s Use A f
17. Oscillations  →  17.1. Simple harmonic oscillations
6. Deformation of solids  →  6.1. Stress and strain
17. Oscillations  →  17.3. Damped and forced oscillations, resonance
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4
A rocket is launched from the surface of the Earth. gives data for the speed of the rocket at two heights above the Earth’s surface, after the rocket engine has been switched off. The Earth may be assumed to be a uniform sphere of radius R = 6.38 ×106m, with its mass M concentrated at its centre. The rocket, after the engine has been switched off, has mass m. Write down an expression in terms of G, M, m, h1, h2 and R for the change in gravitational potential energy of the rocket, m, v1and v2 for the change in kinetic energy of the rocket. Using the expressions in , determine a value for the mass M of the Earth. M = ………………………… kg Use height / m h1 = 19.9 × 106 h2 = 22.7 × 106 v1 = 5370 v2 = 5090 speed / m s–1
5. Work, energy and power  →  5.2. Gravitational potential energy and kinetic energy
13. Gravitational fields  →  13.3. Gravitational field of a point mass
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[T A metal disc is swinging freely between the poles of an electromagnet, as shown in . When the electromagnet is switched on, the disc comes to rest after a few oscillations. State Faraday’s law of electromagnetic induction and use the law to explain why an e.m.f. is induced in the disc. Explain why eddy currents are induced in the metal disc. Use energy principles to explain why the disc comes to rest after a few oscillations. Use metal disc pole-piece of electromagnet
20. Magnetic fields  →  20.5. Electromagnetic induction
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6
An alternating supply of frequency 50 Hz and having an output of 6.0 V r.m.s. is to be rectified so as to provide direct current for a resistor R. The circuit of is used. The diode is ideal. The Y-plates of a cathode-ray oscilloscope (c.r.o.) are connected between points A and B. Calculate the maximum potential difference across the diode during one cycle. potential difference = ………………………… V State the potential difference across R when the diode has maximum potential difference across it. Give a reason for your answer. Use A 50 Hz 6.0 V r.m.s B R [T The Y-plate sensitivity of the c.r.o. is set at 2.0 V cm–1 and the time-base at 5.0 ms cm–1. On , draw the waveform that is seen on the screen of the c.r.o. A capacitor of capacitance 180 µF is connected into the circuit to provide smoothing of the potential difference across the resistor R. On , show the position of the capacitor in the circuit. Calculate the energy stored in the fully-charged capacitor. energy = ………………………… J Examiner s Use 1.0 cm 1.0 cm During discharge, the potential difference across the capacitor falls to 0.43 V0, where V0 is the maximum potential difference across the capacitor. Calculate the fraction of the total energy that remains in the capacitor after the discharge. fraction = ………………………… Examiner s Use
19. Capacitance  →  19.3. Discharging a capacitor
19. Capacitance  →  19.2. Energy stored in a capacitor
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7
[T The photoelectric effect may be summarised in terms of the word equation photon energy = work function energy + maximum kinetic energy of emitted electrons. Explain what is meant by a photon, why most electrons are emitted with kinetic energy less than the maximum. Light of constant intensity is incident on a metal surface, causing electrons to be emitted. State and explain why the rate of emission of electrons changes as the frequency of the incident light is increased. Use
22. Quantum physics  →  22.2. Photoelectric effect
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8
Uranium-234 is radioactive and emits α-particles at what appears to be a constant rate. A sample of Uranium-234 of mass 2.65 µg is found to have an activity of 604 Bq. Calculate, for this sample of Uranium-234, the number of nuclei, number = ………………………… the decay constant, decay constant = ………………………… s–1 the half-life in years. half-life = ………………………… years Use Suggest why the activity of the Uranium-234 appears to be constant. Suggest why a measurement of the mass and the activity of a radioactive isotope is not an accurate means of determining its half-life if the half-life is approximately one hour. Examiner s Use
23. Nuclear physics  →  23.2. Radioactive decay
11. Particle physics  →  11.1. Atoms, nuclei and radiation
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