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Page 1: Stpm Trial Physics Qa Perak

SEKOLAH-SEKOLAH MENENGAH KINTA UTARA, PERAK

GERAK GEMPAR 2012

Instructions to candidates:

DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO.

There are fifty questions in this test. For each question, four suggested answers are given. Choose one correct answer and indicate it on the Multiple Choice Answer Sheet provided. Read the instruction on the Multiple Choice Answer Sheet very carefully. Answer all the questions. Marks will not be deducted for wrong answers. A Data List is provided at the end of this question booklet.

This question paper consists of 12 printed pages STPM 960/1 * This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL

KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA KINTA UTARA KKKIIINNNTTTAAA UUUTTTAAARRRAAA

960/1 STPM

PHYSICS

PAPER 1

MULTIPLE-CHOICE

One hour and forty-five minutes

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1 Two vectors, p and q, are related by the following equations: p + q = r and p2 + q2 = r2 Which of the following statements about p and q is true?

A p is collinear and opposite in direction to q B p is collinear and in the same direction as q C p is perpendicular to q D p is inclined at 45o to q 2 A student uses a micrometer screw gauge to measure the diameter of a steel rod. Based on five measurements, the following results were obtained minimum diameter = 5.28 mm maximum diameter = 5.33 mm mean value = 5.30 mm It is known that the actual diameter is 5.24 mm. What is the most probable reason why the mean value obtained differs from the actual diameter? A There is parallax error. B The number of readings taken is insufficient. C The measuring instrument is not sensitive enough. D There is zero error in the measuring instrument. 3 The graph shows the variation with time of the velocity of a trolley, initially projected up an inclined runway.

What is the maximum distance up the slope which the trolley reaches? A 0.8 m B 1.0 m C 2.0 m D 4.0 m 4 A wheel suddenly detached from a helicopter while it is moving horizontally at 144 km h-1 at a height of 500 m above the earth. What is the horizontal distance travelled by the wheel before it hits the ground? [Take g to be 10 m s-2 and ignore the effects of air resistance and wind ] A 200 m B 300 m C 400 m D 500 m

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5 A child of mass m sits on a car seat which is accelerating horizontally at 0.5g where g is the acceleration of free fall. What is the magnitude of the resultant force F exerted by the car seat on the child?

A 0.50mg B 1.0mg C 1.1mg D 1.5mg 6 A steel ball of mass 5.0 g falls vertically through a liquid at terminal speed 10 cm s-1. The energy dissipated per second in the liquid by the ball’s motion, in mJ, is A 0.025 B 5.0 C 10 D 50 7 The radius of curvature of the North-South Highway at a certain place is 200 m. At what angle must its surface be banked so that a car moving with a speed of 108 km h-1 will not experience any lateral strain on the wheel? A zero B 24.6 C 61.6 D 65.4 8 The diagram shows a metre rule which is placed on a smooth horizontal table. smooth table metre rule impulsive force When a horizontal impulsive force is applied to one end of the meter rule in a direction perpendicular to its axis, the metre rule will experience A translation only. B rotation only. C rotation and translation. D vibration, rotation and translation.

9 m

m A light inextensible string is wound round a disc that can rotate freely about a horizontal axis passing through its centre. A load is tied to the free end of the string. The disc starts to rotate when the load is released from a stationary position. If the radius of the disc is r and the mass of both the disc and the load is m, the angular acceleration of the disc can be expressed as ( moment inertia of the disc about its axis of rotation = ½ mr2 )

A g B gr C rg

32

D rmg

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10 A body of mass m is placed on a rough inclined plane. The angle of inclination is increased gradually until it reached an angle when the mass is just about to slide down. m

The coefficient of static friction is given by A = mg C = mg cos B = mg tan D = tan 11 The diagram shows four positions of a planet which is revolving around the Sun S in an elliptical orbit. The planet moves with minimum speed at position

2 1 S 3 4

A 1 B 2 C 3 D 4

12 The graph on the right shows the variation of the gravitational potential energy U of a spacecraft with its distance r from the Earth’s centre. The radius of the earth is R. If the spacecraft is orbiting the Earth in an orbit of radius ro, the total energy of the spacecraft is

U R ro 0 r - U1 - U2

A - ½ U1 B - ½ U2 C - 2U1 D - 2 U2 13 When the amplitude of a simple harmonic motion changes, which of the following quantities does not change? A period C acceleration B velocity D restoring force 14 The variation of acceleration with displacement of a body moving with simple harmonic motion is as shown in the table below:

x / mm -4 -2 0 2 4 a / mm s-2 16 8 0 -8 -16

The period of oscillation, in seconds, is A 1/ B 2/ C /2 D

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15 Diagrams (a) and (b) show the displacement-distance and displacement-time graphs of a transverse wave. displacement/mm 0 2 4 6 8 distance/cm (a)

displacement/mm 0 5 10 15 20 time/ms (b)

The velocity of the wave is . A 0.004 m s-1 B 0.4 m s-1 C 2 m s-1 D 4 m s-1

16 Which of the following statements is not true about stationary waves? A Particles between consecutive nodes vibrate in phase. B Particles between consecutive nodes vibrate with the same velocity. C Particles between consecutive nodes vibrate with different amplitude. D Particles between consecutive nodes vibrate with the same frequency. 17 A spectator is standing by the side of the track in Sepang. When a Formula-1 racing car passes him, he observed that the pitch of the sound produced by the car decreases. This is due to A Doppler effect. C damping. B resonance. D reflection. 18 A point source produces a sound at the rate of 120 W. What is the intensity level of the sound at a distance of 2.0 m from the source? [ threshold of hearing, Io = 10-12 W m-2 ] A 30 dB B 124 dB C 130 dB D 141 dB 19 The diagram below shows the strain of a wire varies when it is acted upon by a stress. strain O stress The shaded region represents the A strain in the wire. B stress on the wire. C strain energy stored in the wire. D strain energy per unit volume stored in the wire.

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20 The graph shows how the potential energy U between two atoms in a diatomic molecule changes with the distance of separation r between them. At a certain temperature T, each atom vibrates between two positions which are represented by the points P and Q. The maximum thermal energy of the molecule at temperature T is

U 0 r E1 P Q Eo

A Eo B E1 - Eo C E1 + Eo D 2

1 oEE

21 A closed cylinder contains an ideal gas at 2.0 x 10-6 Pa and 27 oC. The number of molecules per unit volume is A 1.1 x 108 m-3 C 4.8 x 1014 m

B 1.2 x 109 m-3 D 5.4 x 1015 m

22 The graph below represents the distribution of molecular speed in a gas at temperature T.

number of molecules, n(v) z speed, v The quantity z is the

A most probable speed. B root mean square speed. C mean square speed. D mean speed. 23 Which of the following equations is not applicable to an ideal gas undergoing an adiabatic change? A dQ = 0 B pV = nRT C pV = constant D TV - 1 = constant

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24 Two conducting blocks are maintained at a temperature difference of 20 K, and are connected through two rods of length 0.4 m and thermal conductivity 25 W m-1 K-1. The cross-sectional area of one of the rods is 1.0 x 10-4 m² while that of the other is 4.0 x 10-4 m². The space between the conducting blocks is filled with lagging. rods lagging cooler hotter block block

The rate of heat flow between the two blocks is A 0.13 W B 0.25 W C 0.31 W D 0.63 W

25 Two identical metal spheres, X and Y, are given positive charges of QX and QY respectively, where QX > QY. Which of the following statements is true about X and Y? A The electric field strength inside both spheres is zero. B The electric potential inside both spheres is zero. C The electric field strength on the surface of both spheres is zero. D The electric potential inside both spheres is the same. 26 An adult has approximately 3.0 x 1028 protons and the same number of electrons. If two adults are standing apart at 500 m, and 0.10 % of the electrons from one of them is transferred to the other, what is the magnitude and characteristic of the electrostatic force between them? magnitude characteristic A zero - B 8.29 x 1023 N attractive C 8.29 x 1017 N repulsive D 8.29 x 1017 N attractive 27 The flash light in a camera consists of a xenon discharge tube which is connected to a capacitor which is charged by a 1 000 V source. The average power supplied to the discharge tube is 2 000 W and the duration of the flash is 0.040 s. Estimate the capacitance of the capacitor. A 40 F B 80 F C 160 F D 80,000 F 28 Lead becomes a superconductor below its critical temperature. Which of the following statements best explained this phenomenon? A The conduction electrons move in pairs. B The vibration of the atoms stopped. C The heat content of the material is zero. D The number of conduction electrons had increased tremendously.

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- 8 - 29 A milliammeter can be converted to a voltmeter by connecting A a resistor of high value in parallel to it. B a resistor of high value in series with it. C a resistor of low value in parallel to it. D a resistor of low value in series with it. 30 Six identical resistors, each of value 5 , are connected to a 2 V cell whose internal resistance can be ignored. X 2 V Y The potential difference across X and Y is

A V32 B V9

8 C V34 D V3

8

31 The diagram shows a 40 cm straight conductor carrying a current of 20 A in a 2.0 T field. The magnetic field acts in the horizontal plane at an angle of θ with the direction of the current.

If the weight of the conductor is 8.0 N and the magnetic force is just enough to balance

the weight of the conductor, what is the angle θ? A 150o B 120o C 60o D 30o 32 The figure shows the trajectories of two charged particles P and Q shot perpendicularly into a region of uniform magnetic field with the same velocity. If the radii of the trajectories are the same, identify P and Q.

P Q A α-particle electron B electron α-particle C electron positron D positron electron

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- 9 - 33 The figure shows the side view of a circular coil of N turns and area A in a magnetic field B. If the normal to the plane of the coil makes an angle α with the magnetic field, the total magnetic flux through the coil is

A NBA cos α B NBA sin α C BA cos α D BA sin α 34

In the circuit above, switch S is closed and the current in the coil is increased gradually by adjusting the rheostat. When the current is at its maximum, switch S is opened. The deflection shown on the galvanometer is largest A at the instant switch S is closed. B while the current in the coil is increasing. C when the current is at its maximum. D at the instant switch S is opened. 35 In a circuit, an alternating current of r.m.s. value 1.00 A flows through a resistor. In another circuit, a steady current of magnitude I flows through an identical resistor. If the two resistors dissipate heat at the same rate, the value of I is

A 0.71 A B 1.00 A C 1.41 A D 2.00 A 36 A sinusoidal voltage of r.m.s. value 0.60 V is connected to a 30 mH inductor. If the peak current flowing through the inductor is 45 mA, what is the frequency of the a.c.?

A 18 Hz B 100 Hz C 110 Hz D 630 Hz

37 The figure shows the symbol of an operational amplifier. Which terminal and label do not

correspond?

Terminal Label A P Inverting input B Q Non-inverting input C R Feedback output D S Signal output

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The diagram above shows a convex lens focusing a parallel beam of light. If a concave lens of focal length 10 cm is placed to intercept the converging light as shown, which of the following statement describes the final image formed? A A real image is formed between the two lenses. B A virtual image is formed between the two lenses. C A real image is formed to the right of the concave lens. D A virtual image is formed to the right of the concave lens. 39 The diagram below shows the intensity distribution produced on a screen by the diffraction of light.

intensity

This can be achieved by using A one single wavelength and a single slit. B one single wavelength and a double slit. C two separate wavelengths and a single slit. D two separate wavelengths and a diffraction grating.

40 In photoelectric emission, the energy of the photon is used A as the kinetic energy of the electron only. B to release the electron from the lattice only. C by the electron to produce a new electron called photoelectron D to release the electron from the lattice and as the kinetic energy of the electron. 41 The figure shows four of the energy levels of an atom. The maximum number of spectral lines produced by the transition of electrons from these four energy levels is

A 3 B 4 C 5 D 6

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42 The graph shows the X-ray spectra I and II produced by an X-ray tube when it is operated at two different voltages. Which statement explains why the minimum wavelength of spectrum II is longer than that of spectrum I?

Rela

tive

inte

nsity

0 Wavelength

A A higher operating voltage is used to produce spectrum II. B A lower operating voltage is used to produce spectrum II. C An element of smaller atomic number is used as the target metal to produce

spectrum II. D An element of bigger atomic number is used as the target metal to produce

spectrum II. 43 The penetration power of X-rays produced from an X-ray tube can be increased by A increasing the length of the X-ray tube. B increasing the operating voltage of the X-ray tube. C increasing the current flowing through the cathode. D changing the target metal to an element of higher atomic number. 44 The nucleus of bismuth Bi209

83 is less stable than the nucleus of iron Fe5626 . Which of

the following is true of the less stable nucleus? A Bigger mass number B Lower ratio of proton to neutron C Lower binding energy per nucleon D Higher binding energy per nucleon 45 A sample consists of 2 g of a radioactive element. The molar mass of the element is 67 g. If the half-life of the element is 78 hours, the activity of the sample after 48 hours is A 2.7 x 1016 s-1 B 2.9 x 1016 s

C 4.4 x 1016 s

D 1.0 x 1020 s

46 A radioactive element X decays to a radioactive element Y which then decays to element Z. If the sample initially contains X only, which of the following factors influences the ratio of the number of Y nuclei to the number of X nuclei after a certain time? A Half-life of element Y C Initial number of X nuclei B Half-life of element Z D Surrounding pressure

I II

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47 When a slow neutron is captured by a stationary Cd11348 nucleus, a Cd114

48 nucleus is formed and a γ-ray photon is emitted. What is the wavelength of the γ -ray?

[Mass of n10 = 1.0087 u, mass of Cd113

48 = 112.9044 u, mass of Cd11448 = 113.9034 u]

A 2.05 x10-23 m C 1.37 x10-13 m B 6.63 x10-16 m D 1.45 x10-12 m

48 YOXN 11

178

nm

147

The equation above represents a nuclear reaction. What do the symbols m, n and Y represent? m n Y A 4 2 nucleon

B 2 4 neutron

C 2 4 proton

D - 1 0 helium nuclide

49 The antiparticle of the electron is the A proton B quark C neutrino D positron 50 The strong force is responsible for A binding the nucleons together. C beta decay. B holding the electrons in the atom. D alpha decay.

960 PHYSICS

Values of constants

Speed of light in free space c = 3.00 x 10 8 m s - 1 Permeability of free space o = 4 x 10 - 7 H m - 1 Permittivity of free space o = 8.85 x 10 - 12 F m - 1 (1/(36)) x 10 - 9 F m - 1 Magnitude of electronic charge e = 1.60 x 10 - 19 C Planck constant h = 6.63 x 10 - 34 J s Unified atomic mass constant u = 1.66 x 10 - 27 kg Rest mass of electron me = 9.11 x 10 - 31 kg Rest mass of proton mp = 1.67 x 10 - 27 kg Molar gas constant R = 8.31 J K - 1 mol - 1 Avogadro constant L, NA = 6.02 x 10 23 mol - 1 Boltzmann constant k = 1.38 x 10 - 23 J K -1 Gravitational constant G = 6.67 x 10 - 11 N m 2 kg - 2 Acceleration of free fall g = 9.81 m s - 2

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960/2

PHYSICS (FIZIK)

PAPER 2 (KERTAS 2)

STRUCTURE AND ESSAY (STRUKTUR DAN ESSEI)

Two and a half hours (Dua setengah jam)

PEPERIKSAAN GERAK GEMPUR

SIJIL TINGGI PERSEKOLAHAN MALAYSIA

Instructions to candidates:

DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE TOLD TO DO SO. Answer all questions in Section A. Write your answer in the spaces provided. Answer any four questions in Section B. Write your answers on the answer sheets provided. Begin each answer on a fresh sheet of paper and arrange your answers in numerical order. Tie your answer sheets to this question paper. All working should be shown. For calculations, relevant values of constants in the Data Booklet should be used. For numerical answers, units should be quoted wherever they are appropriate. Answers may be written in either English or Bahasa Malaysia. A Data Booklet is provided. Arahan kepada calon: JANGAN BUKA KERTAS SOALAN INI SEHINGGA ANDA DIBENARKAN BERBUAT DEMIKIAN. Jawab semua soalan dalam bahagian A. Tulis jawapan anda dalam ruang yang disediakan. Jawab mana-mana empat soalan dalam bahagian B. Tulis jawapan anda pada helaian jawapan yang dibekalkan. Mulakan setiap jawapan pada helaian kertas yang baharu dan susun jawapan anda mengikut tertib berangka. Ikat helaian jawapan anda bersama dengan kertas soalan ini. Semua kerja hendaklah ditunjukkan. Bagi penghitungan, nilai pemalar yang berkaitan dalam Buku Data hendaklah digunakan. Bagi jawapan berangka, unit hendaklah dinyatakan di mana-mana yang sesuai. Jawapan boleh ditulis dalam bahasa Inggeris atau Bahasa Malaysia. Buku Data dibekalkan.

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Section A [40 marks] Answer all questions in this section.

1. a) What is meant by the dimension of a physical quantity? [1] b) Show that the equation relating the current density, J , in a wire to the drift speed, v, of the electrons, J = nve , where e is the charge of an electron and n is the number density of electrons, is dimensionally correct. [4] 2. a) A baseball is projected into the air at an angle to the ground. As it moves through its trajectory, its velocity and, therefore, its momentum constantly changes. Is this a violation of conservation of momentum? Justify your answer. [3] b) The jet of water from a hose has a cross-sectional area of 600 mm2 and a speed of 15 m s-1 when it strikes a wall at right angles and is brought to rest. What is the force exerted on the wall by the jet of water? (The density of water is 1000 kg m-3) [3]

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3. A stone is thrown upward from the top of a building at an angle of 30.0o to the horizontal and with an initial speed of 20.0 m s-1, as shown in the diagram below. 20.0 m s-1 The height of the building is 45.0 m. 30.0o a) Determine the time taken for the stone to reach the ground. [3] 45.0 m b) Calculate the speed of the stone just before its strikes the ground. [3]

4. A small source emits sound waves with a power output of 80 W. Find the distance at which the sound level is 40 dB. (Given that the threshold of hearing Io = 10-12 W m-2) [5]

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5. The graph below shows the variation of the force F between two atoms with separation r between them. F r1 r2 0 r -F

a) On the graph above i) shade the area which represents the energy required to separate completely the two atoms. [1] ii) mark with letter Q, that is the separation between atoms when the resultant force is repulsive. [1]

b) State the physical meaning for the portion of the graph above i) r1, the value of r, when F = 0 [1] ii) r2, the value of r when F is a minimum. [1]

6. Consider three point charges at the corners of a triangle, as shown in the diagram below. y 4.00 m

- + q2 q3

5.00 m q1 + x Given q1 = 6.00 x 10-9 C, q2 = - 2.00 x 10-9 C, q3 = 5.00 x 10-9 C, and the distances of separations are shown in the diagram. Find the magnitude of the resultant force on q3. [6]

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7. The diagram below shows a circuit consisting two resistors and two cells of negligible internal resistance. The values of e.m.f and resistance are as shown. 6V 3V 10 Ω 20 Ω Calculate the power dissipated in the circuit. [4] 8. When a photon of energy E falls on a metal surface an electron may be emitted. Write down, and explain, an equation connecting photon energy, the work function ϕ of the metal and the maximum kinetic energy of the electron. [4]

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Section B [60 marks]

Answer any four questions in this section.

9. a) State Newton’s law of gravitation. [1] b) Use Newton’s law to deduce the gravitational field strength g at an orbit of radius r about the Earth in terms of r, the gravitational field strength go at the Earth’s surface, and the radius rE of the earth (assumed to be a uniform sphere). [3] c) A satellite of mass 600 kg is in a circular orbit at a height 2000 km above the Earth’s surface. Take the radius of the Earth to be 6400 km and the value of go to be 10 N kg-1. Calculate the satellite’s : i) orbital speed [3] ii) kinetic energy [2] iii) gravitational potential energy [3] d) Explain why any resistance to the forward motion of an artificial satellite results in an increase in its speed. [3]

10. a) (i) Explain what is meant by an ideal gas [2] (ii) State two aspects in which a real gas differs from an ideal gas [2] (iii) State the conditions when most gases act like an ideal gas [1]

b) Using simple kinetic energy theory it may be shown that, for an ideal gas, pressure p = ⅓ ρ<c2> , where ρ is the density of the gas and <c2> is the root mean square speed of the molecules. i) Calculate the root mean square speed of hydrogen molecules at pressure 1.01 x 105 Pa and the density of hydrogen is 0.090 kg m-3. [2]

ii) Sketch on the same axes, the molecular speed distribution graphs, number of molecules with speed v against the speed v for two different temperatures. Mark which curve corresponds to the higher temperature. [2]

c) Show how the equation p = ⅓ ρ<c2> may be related to the equation of state for ideal an ideal gas, pV = nRT, where p is pressure, V the volume of n moles, R the molar gas constant and T the absolute temperature. Justify any assumption which you have make.

[5]

11. a) What is meant by eddy current? [2] b) A circuit consists of a coil, a lamp and an a.c. source as shown below.

coil lamp A solid iron core is introduced into the coil. Explain i) why the lamp is dimmer after the core has been introduced, [3] ii) why the core becomes hot. [3]

c) A coil with 200 turns of wire is wrapped on a square frame, 18.0 cm on a side. Each

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turn has the same area, equal to that of the frame, and the total resistance of the coil is 2.0 Ω. A uniform magnetic field is applied perpendicularly to the plane of the coil. If the field changes uniformly from 0 to 0.500 T in 0.8.00s, determine i) the change in flux through the coil during the 0.80-s interval. [3] ii) the magnitude of the induced emf in the coil while the field is changed. [2] iii) the magnitude of the induced current in the coil while the field is changing. [2] 12. The diagram below shows the apparatus used in attempt to measure the wavelength of light using double slit interference. screen d monochromatic light s double slit D

a) Explain how the apparatus produces double slit interference fringes on the translucent screen. [4]

b) The light from the monochromatic source has a wavelength of 5.0 x 10-7 m and it is required to produce a fringe separation of 5.0 mm on the screen 2.00 m from the double slit. Determine the value for s, the distance between the two slits. [3]

c) Calculate the angle separation between neighbouring dark fringes on the screen when viewed from the double slit. [3]

d) Explain any changes that occur to the interference pattern when i) the slit separation in smaller. [1] ii) the lower slit is covered with an opaque material [2] iii) the space between the double slit and the screen is filled with water [2]

13. a) The diagram shows some of the energy levels of the outermost electron in a mercury atom. Level Q represents the lowest possible energy (ground state). 0.0 -1.6 eV - 3.7 eV P - 5.5 eV Q - 10.4 eV i) Explain why a line spectrum results from an atom with such energy levels. [2] ii) Calculate the energy change in joules when the electron moves from level P to level Q, and determine the wavelength of the spectral line associated with this transition. [5] iii) Explain what is likely to happen if a moving electron of energy 7.0 eV collides with

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an isolated mercury atom in its ground state. Explain whether the effect would be different if a photon, also energy 7.0 eV, were to be incident on the atom. [4] b) In an X-ray tube, electrons are accelerated through a potential difference of 300 kV and bombard a target metal. i) Calculate the minimum wavelength of the x-ray emitted. [2] ii) Sketch a graph to represent the X-ray spectrum produced by an X-ray tube. [2] 14. a) State the difference between a fission reaction and a fusion reaction. [2] b) A fusion reactor may involve collisions between deuterium nuclei. i) Explain why the deuterium to be used in a fusion reactor will need to be in a very high temperature. [2] ii) It is thought that the reaction could start when the average energy of the deuterium atoms reaches 1.6 x 10-15 J. Calculate the temperature when this is occurred. [3] c) Two possible ways by which uranium can undergo fission when bombarded with a neutron are

(1) by the release of and as fission fragments, and

(2) by the release of and as fission fragments.

In each case, neutrons are also released. Write an equation for each of the above possibility and determine the number of neutrons released in each of these events. [4]

d) Calculate the total energy released if 1.00 kg of undergoes fission, given that 208 MeV is released per nucleus. [4]

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SEKOLAH-SEKOLAH MENENGAH KINTA UTARA, PERAK

GERAK GEMPAR 2012

Marking scheme

Quest Ans Quest Ans Quest Ans Quest Ans Quest Ans

1 C 11 C 21 C 31 D 41 D

2 D 12 A 22 A 32 D 42 B

3 B 13 A 23 C 33 A 43 B

4 C 14 D 24 D 34 D 44 C

5 C 15 D 25 A 35 B 45 B

6 B 16 B 26 D 36 B 46 A

7 B 17 A 27 C 37 C 47 C

8 C 18 B 28 A 38 C 48 C

9 C 19 D 29 B 39 A 49 D

10 D 20 B 30 A 40 D 50 A

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960/1 STPM

PHYSICS

PAPER 1

MULTIPLE-CHOICE

One hour and forty-five minutes

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Jawapan gerak gempur Fizik II 2012 1. a) The dimensions of a physical quantity express how it is related to the basic quantities mass M, length L, time T, current I, temperature θ and amount of substance N…………………….[1] b) [J] = A m-2 ……………………………………………………….[1]

[nve] = ………………………………………………[2]

…………………………………………………………..[1]

2. a) No ………………………………………………………………….[1] The principle of conservation of momentum states that the momentum of a system is conserved in the absence of external forces……………………………………..[1] The ball is subject to the external force of gravity, so we would not expect its momentum to be conserved. ………………………………………………………….[1] b) rate at which water hits the wall = ρwatervA …………………………[1] = (1000)(15)(600 x 10-6) = 9.0 kg s-1 Force exerted on the wall by the jet of water = rate of change of momentum of the water at wall = vdm/dt ……………..[1] = (15)(9.0) = 140 N ……………….[1] 3. a) use : y = uyot - ½gt2 …………………………………………[1] uyo = 20 sin 30.0 ……………………………………….. [1] - 45.0 = 10t - ½(9.81)t2 t = 4.22 s ……………………………………………… [1] b) vy = uyo – gt = 10.0 – (9.81)(4.22) = - 31.4 m s-1 …………… [1] vx = uxo = 17.3 m s-1 ……………………………………………… [1] = 35.9 m s-1 ………………………………………………. [1] 4. 40 = 10 log(I/Io) ……………………………………………….. [1] 104 = I/Io I = 104Io ………………………………………………………. [1]

I = ……………………………………………………………. [1]

A = 4πr2 ………………………………………………………… [1]

r = = 2.5 10 ………………………… [1]

5. F (i) (ii) any point < r1 Q r1 r2 0 r

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b) i) atomic separation at equilibrium position ………………………………..[1] ii) atomic separation at breaking point ………………………………………[1]

6. F31

- 4.00 m F32 + 37.0o q2 q3

3.00 m 5.00 m + q1

F32 = k | || |

8.99 10. .

.5.62 10 N ………[1]

F31 = 1.08 x 10-8 N θ = 37.0o ………………………………………………………………[1] Fx = F31 cos 37.0o – F32 ………………………………………………………[1] = 3.01 x 10-9 N Fy = F31 sin 37.0o …………………………………………………………… [1] = 6.50 x 10-9 N

FR = 3.01 10 6.50 10 …………………………………….[1] = 7.16 x 10-9 N …………………………………………………………….[1] 7. E = IR ………………………………………………………………………………. [1] 6+3 = I(10 + 20) ………………………………………………………………………. [1] I = 0.3 Power dissipated = I2R1 + I2R2 ………………………………………………………. [1] = (0.3)2(10 + 20) = 2.7 W ……………………………………………………………. [1] 8. energy of photon E = ϕ + ½mv2 m = mass of electron ……………………………………. [1] v = speed of the electron E = all the energy from a photon is transferred to an electron on the metal surface ……[1] ϕ = work function of the metal ia the minimum energy required to remove an electron from the surface of the metal. ………………………………………………………………. [1] ½mv2 = maximum KE where v is the maximum speed of ejection of electron…………. [1] Section B 9. a) All bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of their distance apart. …………………….[1]

b) at Earth’s surface go = …………………….[1]

in orbit radius r,

……………………………………[2]

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c) i) In a circular orbit the free fall acceleration is equal to the centripetal acceleration

so …………………………..[1]

………………………..[1]

.

.7.6 10 ……[1]

ii) KE = ½mv2 = (0.5)(600)(7.6x103)2 = 1.8 x 1010 J ……………………..[2]

iii) PEg = ……………………………………………….[2]

= .

.3.5 10 …………………………….[1]

d) Any resistance will reduce the forward motion of the satellite and the satellite will go into lower orbit …………………………………………………………………………..[2] thus losing PEg and gaining KE……………………………………………….[1] hence it speeds up. 10. a) i) An ideal gas is one that obeys the gas law : PV = RT exactly and under all conditions of temperature and pressure ………………………………………………….[2] ii) - real gas obeys the gas law PV = RT only approximately within a certain range of temperature and pressure. ………………………………………………………………[1] - the molecules in a real gas are acted on by intermolecular forces which assumed to be absent in the case of an ideal gas. ………………………………………………...[1] iii) most gases approach the ideal closely at very low temperature and pressure…[1] b) i) from p = ⅓ ρ<c2>

√ = .

. …………………………………………..[1]

= 1.83 x 103 m s-1 ……………………………………….. [1] Number of molecules n(v) lower temperature higher temperature molecular speed v/ms-1 [2] c) p = ⅓ ρ<c2>

ρ = …………………………………………………………………………….[1]

M = mass of gas containing n moles , V = volume of n moles

average KE of a molecule = ½m<c2> = kT …………………………………[2]

½ M<c2> = nRT

Assume that average KE of a molecule is solely due to its translational and ignore any rotational energy

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Thus <c2> = ……………………………………………………………. [1]

therefore P = ⅓ …………………………………………….[1]

PV = nRT 11. a) i) induced current in a metal plate ii) due to its motion in magnetic field/due to changing in magnetic flux. iii) the direction of eddy current is such that the magnetic field they create oppose the flux change producing them.

[any two] b) i) the inductance of the inductor increases … …………………………………1 which results in an increased in potential difference across it this reduces the p.d across the lamp so that it become dimmer any 2 (note: voltage of a.c source = p.d qcross lamp + p.d across inductor) c) i) Δϕ = ϕf – ϕi = BA – 0 ………………………………..2 = (0.50)(0.18 x 0.18) = 0.0162 Tm2……………………………. 1 ii) ε= N Δϕ/Δt = (200) (0.0162/0.80) = 4.05 V ……………………………. 2 unit : V or Tm2 s-1 iii) ε = IR ……………………………………………………………… 1 I = 4.05/2 = 2.03 A ………………………………………………………… 1 12. a) The single slit acts as a source of light the waves from which are then diffracted by each of the double slits. The double slits act as two coherent sources. These diffracted waves overlap and superpose at the screen to give a bright or a dark region of the interference pattern. The interference formed (the dark and the bright fringes) depending on the path difference (depending on how far they travel to get to P) Path difference = λ or 2λ, etc… they are in phase and form bright fringe Path difference = ½λ or 3/2λ, etc … they are out of phase and form dark fringe. The explanations should mention

Diffraction at the slit or coherent source ……………………………….. 1 Superposition (interference) at the screen ……………………………… 1 Phase difference for bright/ dark fringes ………………………………. 1 Path difference …………………………………………………………. 1

b) ………………………………………………………………. 1

. .

. ……………………………………………………. 1

= 2.0 x 10-4 m …………………………………………………….. 1 c) angular separation of fringes

θ.

.. ………………………… 3

c) i) from ,

a decreases and hence fringe separation x increases ……………….. 1 ii) covering one slit- no more interference pattern ……………………… 1 instead, single slit diffraction pattern shown …………………………. 1 iii) when water filled the space between the double slit and the screen,

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wavelength of light in water is shorter ……………………………… 1 therefore the fringe width x decreases ………………………………. 1 13. a) i) The line spectrum of the atom shown is the result of electron transitions between two particular levels………………………………………………………………………………………. 1 A line emission spectrum is the result when the transition takes place from a higher energy level to a lower one…………………………………………………………………………1 ii) Δ E = (- 5.5 + 10.4) eV ……………………………………………………..1 = 4.9 eV = 4.9 x 1.6 x 10-19 J …………………………………………………….1 = 7.84 x 10-19 J .........................................................................................1

Wavelength λ ………………………………………………………….1

= .

.

= 2.526 x 10-7 m …………………………………………….1 iii) When a moving electron of energy 7.0 eV collides with the isolated mercury- there will be two possibility – the mercury atom would either be excited to second level (-3.7eV) and the surplus energy of 0.3 eV is emitted as photons having the excess energy………1

- Or to the first level (-5.5 eV) . the surplus energy is 2.1 eV and is emitted as photons…………………………………………………………………1

The above effect would be different if a photon of energy 7.0 eV is incident on the atom…..1 There would be no transition of the mercury atom because the difference in energy between the higher excited states and the ground state is not equal to 7.0 eV……………………………. 1

b) i) eV = …………………………………………….. 1

λmin = . .

. = 4.14 x 10-12 m ……………. 1

ii) intensity 0 λmin wavelength shape ……1 Axes ……..1 14. a) Fission reaction occurs when a heavy nucleus splits into two smaller nuclei….. 1 Fusion reaction occurs when two light nuclei combine to form a heavier nucleus… 1 b) i) For two deuterium atoms to collide and unite, they have to overcome their mutual electrostatic repulsion.……………………………………………………………. 1 This occurs when the nuclei approach each other at high speeds when they are raised to very high temperature. …………………………………………………………... 1 (ii) using ½KT = 1.6 x 10-15…………………………………………………………….. 2 T = (2x1.6 x 10-15)/1.38 x 10-23 = 2.3 x 108 K ……………………………. 1

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c) (1) → 2 ……………………………………… 2

(2) → 3 ……………………………………. 2

d) number of nuclei in 1 kg of uranium N = .

1.00 10 …….2

= 2.56 x 1024 nuclei

energy = 2.56 x 1024 nuclei (208 MeV/nucleus) ………………………………. 1

= 5.32 x 1026 MeV ……………………………………………………….1

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