FEBRUARY 2014
PHYSICS
Time Allowed – 2 hours
The exam paper consists of three sections. There is no need for notebook or graph paper: all the answers, including plotting and working out, should be given on the question sheet. In each section, use the space below the question to work out the answers. There are two additional pages at the end of the booklet for extra calculations or notes.
Section Ais data analysis. Section B has five questions. Work out the answers after each question and highlight your numerical answers by underlining or circling them.In your answers, do not forget to indicate the units. Correct approaches, comments, ideas, methods and reasoningmay be marked even if the answer is not completely correct.Section C contains twenty multiple-choice questions. Each question is followed by up tofour potential answers, labelled with letters A to D;only one of them is correct. Indicate your answer by clearly circling the letter of your choice.No negative mark will be given for wrong answers.Each of Sections A and B is worth 20 marks; section C is worth 40 marks.
Standard booklets of fundamental constants, provided by the school, can be used. However, the list on the next page should be enough for answering the questions.
Please attempt to answer ALL questions
Calculators are allowed to be used.
Constants
Electron charge
Electron mass
Gravitational constant
Planck’s constant
Speed of light
Gravitational acceleration
Sound speed in air
Conversions
Astronomical Unit
Ångström1Å = 10–10 m
Day
Electronvolt
Absolute temperature
p (pico): 10–12
n (nano): 10–9
(micro: 10–6
m (milli):10–3
Formulas
Ideal gas equation:
Gravitational force:
Kepler’s 3rd law:
Exponential decay with given half-life:
Energy of electromagnetic wave:
Section A
A toy bee of total mass is suspended from a spring. When it is pulled down and released, it starts to oscillate vertically. The distance of the bee’s nose from the top of the spring, measured at sixteen different times, is shown in the table below.
Time (s) / 0 / 0.6 / 1.2 / 1.8 / 2.4 / 3.0 / 3.6 / 4.2Distance (mm) / 417 / 349 / 208 / 201 / 289 / 390 / 396 / 316
Time (s) / 4.8 / 5.4 / 6.0 / 6.6 / 7.2 / 7.8 / 8.4 / 9.0
Distance (mm) / 230 / 199 / 246 / 344 / 390 / 391 / 331 / 271
The first twelve measurements are plotted in the distance versus time graph below.
a) What uncertainty was assumed in the measurements, on the basis of which the error bars have been added to the data points?
[1]
b) Plot the missing data points on the graph with error bars indicating the same uncertainty.
[2]
c)Connecting the data points, draw a suitable curve on the graph between and that shows how the variation of displacement with time. [2]
d) Measured from the top of the spring, what is the distance of the equilibrium position of the bee’s nose?
[1]
e) By reading from the graph, estimate the amplitude, A, and the period, T, of the oscillation.
[2]
f) Calculate the cyclic frequency, , and the angular frequency, , of the oscillation.
[2]
g) Assuming simple harmonic motion, , write up a function of time for the displacement, by replacing the parameters , , , and by suitable values,that approximates the oscillatory motion of the bee’s nose.
[2]
h) Besides the displacement, the speed of the toy also oscillates between zero and a maximum value.
h1) At which position is the bee’s speed zero?
[1]
h2) Estimatethe maximum speed of the bee.
[1]
i) Work out the stiffness, , of the spring.
[1]
j) Using the displacement versus time function in question (g), work out the position of the bee’s nose at . Does that prediction agree with the last measured distance given in the table?
[2]
k) Name three aspects of the oscillation that introduce uncertainty or error to the derived characteristic parameters of the motion?
[3]
Section B
1
A box of mass is on the top of a table that can carry a maximum weightof . The table, with the box on it is taken to an upper floor in an elevator. At what rate does the elevator accelerate if the table top is found broken? (g = 9.8 m/s2) [4]
2
A car is leaving a petrol station with zero initial speed at and is moving on a long horizontal straight road with constant acceleration for four seconds. At, the driver suddenly changes the acceleration to and keeps this new acceleration until she arrives back at the petrol station. (The negative sign of indicates that the acceleration has changed to the opposite direction.)
a) When is the car the farthest from the petrol station? [2]
b) When will the car get back to the petrol station? [2]
3
Satellite A and satellite B are orbiting the Earth. The height of A above the surface of the Earth is , while the height of B is , where is the Earth’s radius. What is the ratio between the orbital periods of the two satellites, [4]
4
The minimum light intensity that the eye of an owl is sensitive tois. Supposed that the pupil of the owl’s eye can expand to a circle of diameter, at least how many photons of wavelength have to reach the owl’s eye per second so that the bird can sense light? (, ) [4]
5
The graph shows the mass of a radioactive material as a function of time.
What will be the mass of the material in t = 5 minutes? [4]
Section C
1) How does the speed of a small free-falling object change during the fourth second of its fall?
A)It does not change.B) It increases by a factor of 4/3.
C) It increasesby a factor of9/4.D) It increases by a factor of16.
2) According to our current knowledge, which of the following planets has satellites?
A)MercuryB) MarsC) BothD)None of them
3) Andrew pushes,with a constant low speed,a sofa from one corner of a living room to another on a horizontal surface. Then Barbara pushes the same sofa back to its original position in the same way but with a constant high speed. Which of the following statements is correct? Assume that friction does not vary with speed.
A)Andrew does more work than Barbara.
B)Andrew does the same amount of work as Barbara.
C)The power of Andrew’s action is more than the power of Barbara’s action.
D)The power of Andrew’s action is the same as the power of Barbara’s action.
4) What value of resistance can be made by using two resistors of 2 Ω and 3 Ω?
A)1.2 ΩB) 1.5 ΩC) 2.5 ΩD) 6 Ω
5) How much greateris the average angular speed of the minute hand of a clock than that of the hour hand?
A)They are the same. B) 6 times biggerC) 12 times biggerD) 60 times bigger
6) When point charge A is placed at distance l from point charge B, the force acting on point charge A is F = 100 N. What force will act onA if we put point charge C halfway between A and B, assuming that the charges of B and C are equal, ?
A) F = 200 NB) F = 300 NC) F = 300 ND) F = 500 N
7) What is particle ‘X’ in the following nuclear process?
A) A neutronB) An alpha particleC) A beta particleD) A proton
8) Where is the Solar System relative to the Milky Way?
A)The Milky Way is part of the Solar System.
B)The Solar System is the nearest stellar system to the Milky Way.
C)The Solar System is between the centre and the edge of the Milky Way.
D)The Solar System is in the centre of the Milky Way.
9) A bicycle slows down from to . Its kinetic energy reduces…
A)by a factor of four.B) by half.
C) by a factor of .D) by a factor of ten.
10) Is it possible for a proton to stay continuously at rest in a medium embedded innon-zero homogeneous electric and magnetic fields which are constant over time?
A)Yes, if the electric and magnetic forces are the same and point in the opposite
direction.
B)No, as the only force acting on the proton is the electric force.
C)Yes, because electromagnetic forces act only on a moving particle.
D)No, as the electric and magnetic forces are always perpendicular to each other.
11) What can we find out from the frequency spectrum of an atom?
A)The energy differences between the electron states of the atom
B)The binding energy of the nucleus
C)The number of electrons in each energy state
D)The atomic mass
12) A particle is performing a circular motion with period T. The radius of the circle is R. What is its displacement over?
A)B)d = 2RC) D)
13) Can water be boiled at room temperature?
A)Yes, if the pressure is low enough.
B)Yes, if we gradually transfer a large enough amount of heat to it.
C)Yes, if it is clear H2O and the container is not touched or disturbed in any way.
D)No, it can only evaporate but not boil.
14) The unit of which physical quantity is the same as the unit of torque, ?
A)PressureB) EnergyC) Linear momentumD) Power
15) Ten penguins are marching on a straight, horizontal line in the snow at the constant speed of and with the same distance of between them. Due to a sudden snow storm, each of them instantaneously slows down and continues their journey with the constant speed of . What happens to their distance, d, due to going slower?
A) It decreases.B) It remains the same.C) It increases.
D) It Decreases near the front of the row and increases at the back.
16) Consider an undergroundcave and a seaside beach. Therelative humidity is the same at the two places. The air at which place contains more water per unit volume?
A) The cave.
B) The seaside beach.
C) The air at the two placescontain the same amount of water per unit volume.
D) Rhere is not enough information to answer the question.
17) The number of which particles increases during the nuclear fusion in the solar core?
A) Hydrogen atomsB)Protons C) Nucleons D) Helium molecules
18) Beryllium, , has four protons, five neutrons and four electrons. A beryllium atom is ionised by removing three of its electrons on-by-one. The removal of which electron requires the largest amount of energy?
A) The first electron.B) The second electron.C) The third electron.
D) It is the same for all, as the required energy only depends on the kinetic energy of the electrons.
19) During a thermodynamic process, the volume of a closed container expands from to , while the temperature of the ideal gas in the container increases from to . What happens to the gas pressure during the process?
A) The pressure decreases by about a factor of three.
B) The pressure increases by fifty per cent.
C) The pressure increases by a factor of six.
D) There is not enough data to answer the question.
20) The voltage in a circuit can be given by the following function of time:
,
wheret is measured in seconds.What is the maximum value the voltage takes?
A) B) C) D)
Notes:
Notes:
1