0625_w13_qp_33
A paper of Physics, 0625
Questions:
11
Year:
2013
Paper:
3
Variant:
3
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1
For Examiner’s Use An archaeologist digging at an ancient site discovers a spoon. The spoon is made from an unidentified material. The archaeologist suspects that the spoon is made of metal. She places it above a flame, as shown in . She notices that the handle of the spoon quickly becomes very hot. State why this observation supports the suggestion that the spoon is made of metal. Describe, in terms of its atoms, how thermal energy is transferred through a metal. For Examiner’s Use The archaeologist hopes that, by determining its density, she will be able to identify the metal. Describe a method for determining the density of the metal from which the spoon is made.
2. Thermal physics  →  2.2.1. Thermal expansion of solids, liquids and gases
2. Thermal physics  →  2.3.1. Conduction
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2
For Examiner’s Use A spring S is suspended from a clamp stand in a school laboratory. A student hangs various masses from the end of S and determines the extension x produced by each mass. Calculate the weight of a 250 g mass. weight = The student plots a graph of the force F applied to the spring against the extension x. is the student’s graph. 6.0 5.0 4.0 3.0 2.0 1.0 P x / cm F / N At point P on the graph, the line begins to curve. State the name given to point P. Use the section of the graph where spring S obeys Hooke’s law (F = kto determine the spring constant k of the spring. k = For Examiner’s Use shows a mass of 0.12 kg resting on the bottom of a box. mass spring box A spring that is identical to S connects the mass and one side of the box. Ignore friction between the mass and the box. The box and the mass are at rest. State the resultant force acting on the mass. force = The box is firmly attached, in a horizontal position, to the body of a racing car. As the car accelerates the spring stretches by 2.0 cm. 1. Using , determine the tension in the spring. tension = 2. Calculate the acceleration of the mass produced by this tension. acceleration =
1. Motion, forces and energy  →  1.5.1. Effects of forces
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3
For Examiner’s Use shows a fork-lift truck lifting a crate on to a high shelf in a warehouse. fork-lift truck crate The fork-lift truck lifts a crate of weight 640 N through a vertical distance of 3.5 m in 4.0 s. Calculate the useful work done in lifting the crate. work done = A motor drives a mechanism to lift the crate. The current in the motor is 25 A. The motor is connected to a 75 V battery. Calculate the energy supplied to the motor in 4.0 s, energy = the overall efficiency of the fork-lift truck in lifting the crate. efficiency = For Examiner’s Use Not all of the energy supplied is used usefully in lifting the crate. Suggest two mechanisms by which energy is wasted. 1. 2.
1. Motion, forces and energy  →  1.7.3. Energy resources
1. Motion, forces and energy  →  1.7.2. Work
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4
For Examiner’s Use A child’s toy launches a model parachutist of mass 0.40 kg vertically upwards. The model parachutist reaches a maximum height of 8.5 m. Calculate the gravitational potential energy gained by the model parachutist, energy = the minimum possible speed with which the model parachutist was launched. speed = In practice, the launch speed must be greater than the value calculated in . Explain why. As the model parachutist returns to the ground, it loses gravitational potential energy. Explain what happens to this energy as the model parachutist falls through the air at constant speed.
1. Motion, forces and energy  →  1.7.1. Energy
1. Motion, forces and energy  →  1.2. Motion
6. Space physics  →  6.1.2. The Solar System
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5
For Examiner’s Use The Sun is a large sphere of high temperature gas. An extremely large quantity of energy radiates from the Sun into space every second. A process releases energy inside the Sun and its temperature stays high. State the name of this process. A gardener stores water in a large, cylindrical metal drum. The drum is painted black and has no lid. On a bright, sunny day, the water evaporates quickly and the water level in the drum falls. Suggest how, by using a drum of a different shape, the gardener can reduce the quantity of water lost by evaporation. The gardener is told that, by painting the drum white, he can reduce the quantity of radiation absorbed and so reduce the rate of evaporation. Describe an experiment to show that black surfaces are better absorbers of radiation than white surfaces. You may include a diagram.
2. Thermal physics  →  2.3.3. Radiation
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6
For Examiner’s Use A student uses a 2400 W electric kettle to obtain a value for the specific heat capacity of sunflower oil. shows the apparatus. plug thermometer kettle watch measuring jug The student uses a measuring jug and pours 1.5 kg of sunflower oil into the empty kettle. He uses a thermometer to measure the temperature of the oil. The kettle is switched on and left on for 50 s. The temperature of the oil increases by 32 °C. The student assumes that all the electrical energy is transferred as thermal energy to the oil. Calculate the value for the specific heat capacity of sunflower oil obtained by the student. specific heat capacity = State and explain whether the value for the specific heat capacity obtained by the student is too large or too small.
2. Thermal physics  →  2.2.2. Specific heat capacity
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7
For Examiner’s Use A ray of light from a laser passes from air into a clear, semi-circular, plastic block. shows the ray entering the block. normal 40° light ray plastic block The ray continues in the same direction and meets the middle of the opposite surface at an angle of 40 ° to the normal. The refractive index of the plastic is 1.5. The ray continues into the air. Calculate the angle between the normal and the path taken by the light after it leaves the block. angle = For Examiner’s Use The frequency of the light produced by this laser is 3.8 × 1014 Hz and its wavelength in the plastic block is 5.3 × 10–7 m (0.000 53 mm). Calculate the speed of light in this plastic, speed = the speed of light in air. speed = Explain why the ray does not change direction as it enters the plastic block.
3. Waves  →  3.2.1. Reflection of light
3. Waves  →  3.2.2. Refraction of light
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8
For Examiner’s Use An a.c. power supply is connected in series with a metal-filament lamp. A cathode-ray oscilloscope (c.r.o.) is in parallel with the lamp, as shown in . is the trace seen on the c.r.o. screen. power supply lamp cathode-ray oscilloscope A diode is inserted in the circuit, as shown in . power supply lamp cathode-ray oscilloscope On , draw the shape of the trace now seen on the screen. Suggest a device that uses a diode in this way. State and explain the effect on the lamp of inserting the diode into the circuit.
4. Electricity and magnetism  →  4.2.4. Resistance
4. Electricity and magnetism  →  4.3.1. Circuit diagrams and circuit components
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9
For Examiner’s Use The a.c. supply from a power station is connected to the primary coil of a transformer. The secondary coil is connected to long-distance transmission cables. The output voltage of the transformer is greater than the input voltage. Explain how a transformer produces this output voltage. There are energy losses in the transmission cables. Explain why the energy losses become greater when the length of the transmission cables is greater. Discuss the advantages and disadvantages of using transmission cables of greater cross-sectional area.
4. Electricity and magnetism  →  4.5.6. The transformer
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10
For Examiner’s Use 10 shows a variable resistor and a solenoid (long coil) connected to a battery. solenoid variable resistor battery The current in the solenoid produces a magnetic field. On , draw lines to show the pattern of the magnetic field due to the current. State the feature of the pattern of the magnetic field lines that indicates the strength of the magnetic field at particular points. State and explain the effect on the magnetic field of increasing the resistance of the variable resistor. For Examiner’s Use In a laboratory vacuum chamber, some current-carrying coils produce a very strong magnetic field near a source of α-particles. shows the arrangement. _-particle source path of _-particles uniform magnetic field into page In the shaded region of , draw a possible path for the α-particles in the magnetic field. State and explain the effect on this path of reversing the current in the coils.
4. Electricity and magnetism  →  4.5.3. Magnetic effect of a current
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11
For Examiner’s Use 11 In a laboratory at a nuclear power station, a radiation detector is connected to a computer. The readings recorded are displayed on the computer screen. The detector is switched on. Ten minutes later, at time t = 10 minutes, a small sample of radioactive material is removed from a nuclear reactor and placed near to the detector. Readings are recorded for a further 40 minutes. shows the display. time t / minutes count-rate counts / minute Use to determine the background count-rate in the laboratory. background count-rate = Use to determine the count-rate due to the radioactive sample at t = 10 minutes, count-rate due to sample = at t = 19 minutes. count-rate due to sample = For Examiner’s Use Use the values obtained in to estimate the half-life of the radioactive sample. half-life =
5. Nuclear physics  →  5.2.1. Detection of radioactivity
5. Nuclear physics  →  5.2.4. Half-life
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