# M13/4/PHYSI/SPM/ENG/TZ1/XX

## Presentation on theme: "M13/4/PHYSI/SPM/ENG/TZ1/XX"— Presentation transcript:

M13/4/PHYSI/SPM/ENG/TZ1/XX
Physics Standard level Paper 1 Monday 6 May 2013 (morning) 45 minutes

M13/TZ1 1. The mass of an elephant is 104 kg. The mass of a mouse is 10–2 kg. What is the ratio mass of the elephant? mass of the elephant mass of the mouse ? A. 10–8 B. 10–6 C. 106 D. 108 C 2. An archer aims five arrows at the centre of a target. The arrows strike the target as shown below. Which of the following describes the aim of the archer? A. Accurate and precise B. Accurate but not precise C. Precise but not accurate D. Neither accurate nor precise C

M13/TZ1 3. The graph below shows how velocity v varies with time t for a ball thrown vertically upwards from the Earth’s surface. The shaded area is equal to the A. displacement. B. final velocity. C. change in velocity. D. acceleration. A 4. Two identical balls are dropped from a tall building, one a few seconds after the other. Air resistance is not negligible. As the balls fall, the distance between the balls will A. decrease. B. increase. C. increase then remain constant. D. remain constant. No air resistance y = 5 t2 when a = 0 y = v t v is terminal speed time distance 1 s 5 m 2 s 20 m 3 s 45 m 4 s 80 m C

M13/TZ1 5. Which of the following is always true for an object moving in a straight line at constant speed? A. No forces act on the object. B. No resultant force acts on the object. C. The momentum of the object is zero. D. No work is being done on the object. moving in a straight line at constant speed → constant velocity Translational equilibrium: 𝑣 is const. → 𝑎 =0 → 𝐹 𝑛𝑒𝑡 =0 B 6. A person of weight 600 N is standing on a weighing scale in a lift (elevator). The lift is accelerating upwards at 1.0 m s–2. Which of the following is the reading on the scale? A. 0 N B. 540 N C. 600 N D. 660 N Fnet = ma Fn – 600 = 60 Fn = 660 N D

M13/TZ1 7. A spaceship is moving at constant speed in outer space.
An internal explosion causes it to break into two pieces that move in opposite directions. Which of the following best describes what happens to its total momentum and total kinetic energy as a result of the explosion? Total momentum Total kinetic energy A. unchanged B. increased C. D. Momentum is conserved as the system is isolated. Kinetic energy obviously increases as the result of internal explosion. B

M13/TZ1 8. A horizontal disc is rotating about a vertical axis through its centre. Points P and Q on the disc are at distances R and 2R respectively from the centre. The acceleration at P is a. Which of the following is the acceleration at Q? A. 0.5a B. a C. 2a D. 4a 𝑎 𝑐 = 𝑣 2 𝑅 𝑃: 𝑎 𝑐 = 𝑣 2 𝑟 = 2𝜋𝑅 𝑇 2 𝑅 = 4 𝜋 2 𝑅 𝑇 2 𝑄: 𝑎 𝑐 = 𝑣 2 𝑟 = 2𝜋2𝑅 𝑇 𝑅 = 8 𝜋 2 𝑅 𝑇 2 C kg of water at 100 °C is mixed with 1.0 kg of water at 0 °C in a container insulated from the surroundings. Which of the following is the final temperature of the water? A. 20 °C B. 25 °C C. 75 °C D. 80 °C Thermal energy given by hot water = thermal energy received by cold water m1 c1 (100 – T) = m2 c2 (T – 0) c1 = c2 4.0 (100 – T) = 1.0 T ⟹ 400 – 4 T = T D

10. Which of the following best describes the evaporation of a liquid?
M13/TZ1 10. Which of the following best describes the evaporation of a liquid? Location of process Temperature at which process can occur A. at surface at any temperature of liquid B. at maximum liquid temperature only C. throughout liquid D. A 11. Which of the following is the temperature of an object related to? A. The kinetic energy of the object B. The random kinetic energy of the particles in the object C. The potential energy of the particles in the object D. The sum of the random kinetic energy and potential energy of the particles in the object B

12. The acceleration of an object executing simple harmonic motion is proportional to the
A. displacement of the object from equilibrium. B. velocity of the object. C. amplitude of oscillation. D. frequency of oscillation. M13/TZ1 A Simple Harmonic Motion is periodic motion in which the acceleration/ restoring force is proportional to and in opposite direction of the displacement. 𝑎=− 𝜔 2 𝑥 𝐹=− 𝑚𝜔 2 𝑥 𝜔 𝑖𝑠 𝑎𝑛𝑔𝑢𝑙𝑎𝑟 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦= 2𝜋 𝑇 13. A system, consisting of a mass M connected to a spring, oscillates on a frictionless surface with simple harmonic motion between two points, X and Y. Point O is the centre of the oscillation. For the system, at which of the following points is the elastic potential energy equal to the kinetic energy? A. O only B. X and Y only C. O, X and Y D. Neither O, X nor Y v = ± ω (x02 – x2)1/ → D

M13/TZ1 14. Microwave ovens cause the water molecules in food to resonate. Water molecules have a natural frequency of vibration f . In order to heat the food most effectively, the frequency of the microwaves should have a value A. less than f . B. equal to f . C. greater than f . D. as large as possible. Natural frequency is the frequency an object will vibrate with after an external disturbance. B resonance: The increase in amplitude of oscillation of a system exposed to a periodic driving force with a frequency equal to the natural frequency of the system. If the frequency of a driving force matches the natural frequency of the system, this leads to a better absorption of energy by the system, resulting in large amplitude oscillations.

M13/TZ1 15. Gas particles are equally spaced along a straight line. A sound wave passes through the gas. The positions of the gas particles at one instant are shown below. Which of the distances shown is equal to the wavelength of the wave? B Wavelength λ: the distance, measured in the direction of propagation of a wave, between two successive points with the same phase of oscillation. 16. A particle with positive charge +q moves freely from one plate held at potential V1 to another plate held at potential V2. Which of the following is the electric potential energy lost by the charge? A. qV1 B. qV2 C. q (V1 +V2 ) D. q (V1 – V2 ) ∆𝑈=𝑞∆𝑉 D

M13/TZ1 𝑅= 𝑉 𝐼 by definition
17. Which of the following graphs shows the relationship between current I and voltage V for a filament lamp? 𝑅= 𝑉 𝐼 by definition Filament does not obey Ohm’s law because ratio voltage to current is not constant. We say tungsten is “non-ohmic” It’s resistance increases as current through it increases, because temperature increases. D

A voltmeter is connected across one of the lamps.
M13/TZ1 18. A cell of negligible internal resistance is connected to three identical lamps. A voltmeter is connected across one of the lamps. If the filament in lamp X breaks, the reading on the voltmeter will A. become zero. B. decrease. C. stay the same. D. increase. B V = IR R doesn’t change Current in the circuit flowing through resistor will be smaller if X breaks, because resistance of the parallel connection will increase, so will total resistance of the circuit, what results in smaller current.

M13/TZ1 19. The gravitational field strength at the surface of a certain planet is g. Which of the following is the gravitational field strength at the surface of a planet with twice the radius and twice the mass? A. 𝑔 2 B. g C. 2g D. 4g A Force between planet (mass M) and object of mass m is weight of that object. So 𝑚𝑔=𝐺 𝑀𝑚 𝑅 2 R – distance between center of the planet and object m = radius of the planet. 𝑔=𝐺 𝑀 𝑅 → 𝑔 𝑛𝑒𝑤 =𝐺 2𝑀 (2𝑅) 2 = 𝑔 2

M13/TZ1 20. Two point charges of size +2q and –q are placed as shown below. In which of the regions I, II and III can the resultant electric field strength be zero? A. I only B. II only C. III only D. I and III only In region I electric field due to (+2q) is to the left and electric field due to (–q) is to the right, but one due to (+2q) is always greater then the other one. In region II both electric fields are to the right In region III electric field due to (+2q) is to the right and electric field due to (–q) is to the left, and there is the point at which the are equal in magnitude but in opposite direction resulting in zero resultant electric field. C

21. A wire is placed in a magnetic field which is directed to the right. The wire carries
a current directed into the page. Which of the following is the direction of the force on the wire? M13/TZ1 D R-H-R 1: The direction of the magnetic force on a charge/current is given by the right-hand rule 1 Outstretch fingers in the direction of v (or current I). Curl fingers as if rotating vector v (I ) into vector B. Magnetic force on a positive charge (or I) is in the direction of the thumb Magnetic force on a negative charge points in opposite direction. .

A. Placing the sample in a lead container
M13/TZ1 22. Which of the following would decrease the initial activity of a sample of plutonium? A. Placing the sample in a lead container B. Placing the sample in a dark room C. Decreasing the mass of the sample D. Decreasing the temperature of the sample C

What is the activity after 6 days? A. 2 Bq B. 3 Bq C. 4 Bq D. 6 Bq
M13/TZ1 23. A radioactive sample of initial activity 12 Bq has a half-life of 3 days. What is the activity after 6 days? A. 2 Bq B. 3 Bq C. 4 Bq D. 6 Bq B After 3 days activity is half of the initial one = 6 Bq After next 3 days activity is half of that one = 3 Bq 24. The reaction is an example of A. alpha decay. B. artificial transmutation. C. nuclear fusion. D. proton decay. B

What is the efficiency of the car? A. 30 % B. 40 % C. 70 % D. 100 %
M13/TZ1 25. The diagram below shows an energy flow diagram (Sankey diagram) for a car. What is the efficiency of the car? A. 30 % B. 40 % C. 70 % D. 100 % A 𝑒𝑓𝑓= 𝑢𝑠𝑒𝑓𝑢𝑙 𝑜𝑢𝑡𝑝𝑢𝑡 𝑖𝑛𝑝𝑢𝑡 = 30𝑘𝐽 100𝑘𝐽

𝑀𝑊= 𝑀𝐽 1𝑠 → 𝑜𝑢𝑡𝑝𝑢𝑡=0.25 30 𝑀𝐽 𝑘𝑔 −1 50 𝑘𝑔/𝑠
M13/TZ1 26. A small biofuel power station burns ethanol with an overall efficiency of 25 %. The energy density of ethanol is 30 MJ kg–1. The mass of fuel consumed every second is 50 kg. Which of the following gives the useful power output in MW? A 𝑀𝑊= 𝑀𝐽 1𝑠 → 𝑜𝑢𝑡𝑝𝑢𝑡= 𝑀𝐽 𝑘𝑔 − 𝑘𝑔/𝑠 = (30×50) 𝑀𝐽 𝑘𝑔 −1 𝑘𝑔 𝑠 = 25×30× 𝑀𝐽 𝑠

M13/TZ1 27. An oscillating water column ocean-wave energy converter produces power P from waves of a certain amplitude and wavespeed. Which of the following would be the power produced from waves of twice the amplitude and twice the wavespeed? A. 2P B. 4P C. 8P D. 16P Wave power: P/L amplitude of the wave A, length of wavefront L,  - density of water C

M13/TZ1 28. The total power radiated by the Sun is P. The distance from the Sun to the Earth is d. The albedo of the Earth is α . What is the power absorbed by each square metre of the Earth’s surface? 𝛼= 𝑡𝑜𝑡𝑎𝑙 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑 𝑠𝑐𝑎𝑡𝑒𝑟𝑟𝑒𝑑 𝑝𝑜𝑤𝑒𝑟 𝑡𝑜𝑡𝑎𝑙 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑝𝑜𝑤𝑒𝑟 𝐼𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦: 𝐼= 𝑃 4𝜋 𝑑 2 𝐴𝑝𝑝𝑎𝑟𝑒𝑛𝑡 𝑏𝑟𝑖𝑔ℎ𝑡𝑛𝑒𝑠𝑠: 𝑏= 𝑃 4𝜋 𝑑 2 D 𝛼= 𝑠𝑐𝑎𝑡𝑒𝑟𝑟𝑒𝑑 𝑖𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 𝑡𝑜𝑡𝑎𝑙 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑖𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 Intensity scattered = 𝛼 (total incident intensity) Intensity absorbed = total incident intensity – Intensity scattered = total incident intensity – 𝛼 (total incident intensity )

M13/TZ1 29. Carbon dioxide is a greenhouse gas because

M13/TZ1 30. Which of the following is most likely to increase the rate of global warming? A. Deforestation B. Increasing the use of nuclear power stations C. Increasing the use of renewable energy sources D. Using natural gas instead of coal for electricity generation A

M13/4/PHYSI/SPM/ENG/TZ2/XX
Physics Standard level Paper 1 Monday 6 May 2013 (afternoon) 45 minutes

electric field strength is not a magnitude
M13/TZ2 The length of the side of a cube is 10.0 ±0.3 cm. What is the uncertainty in the volume of the cube? A. ±0.027 cm3 B. ±2.7 cm3 C. ±9.0 cm3 D. ±90 cm3 ∆𝑉 𝑉 = ∆𝑎 𝑎 + ∆𝑎 𝑎 + ∆𝑎 𝑎 =3 ∆𝑎 𝑎 D ∆𝑉=3 𝑎 2 ∆𝑎=90 𝑐𝑚 3 2. Which of the following lists three vector quantities? A. momentum, electric field strength, displacement B. momentum, displacement, pressure C. pressure, electric current, displacement D. electric current, electric field strength, impulse A electric field strength is not a magnitude It is the whole vector

3. An object, initially at rest, travels a distance d in a time t at a constant acceleration.
What is the time taken for the object to travel 16d from rest at the same acceleration? A. 16t B. 8t C. 4t D. 2t M13/TZ2 𝑑= 𝑎 2 𝑡 → 𝑑= 𝑎 2 (4𝑡) 2 C 4. An object is released above the surface of Earth. Which of the following correctly describes the speed and acceleration before it reaches terminal speed? Speed Acceleration A increases remains constant B increases decreases C remains constant remains constant D remains constant decreases B Air resistance provides a drag force to objects in free fall. ▪ The drag force increases as the speed of the falling object increases resulting in decreasing downward acceleration ▪ Although acceleration decreases, the speed still increases ▪ When the drag force reaches the magnitude of the gravitational force, the falling object will stop accelerating and fall at a constant velocity. This is called the terminal velocity/speed.

M13/TZ2 5. An object of mass m is connected via a frictionless pulley to an object of mass M, where M > m. M rests on a horizontal frictionless surface. What is the acceleration of the system? 𝐹 𝑛𝑒𝑡 =𝑚 𝑎 T = Ma mg - T = ma mg - Ma = ma a(M+m)=mg A

M13/TZ2 6. The graph shows the variation with distance x of the magnitude of the net force F acting on a body initially at rest. Which of the following describes how the kinetic energy and the acceleration of the body change with distance? Kinetic energy Acceleration A. decrease decrease B. decrease increase C. increase decrease D. increase increase 1. ∆ KE = W net work done on an object will result in the change of kinetic energy (work is the area under the graph F vs. x) 2. As net F decreases, so does acceleration C

M13/TZ2 7. A ball of mass 0.40 kg travels horizontally and strikes a vertical wall with a speed of 5.0 m s–1. It rebounds horizontally with a speed of 3.0 m s–1. The ball is in contact with the wall for a time of 0.20 s. What is the average magnitude of the force exerted by the ball on the wall? A N B N C. 4 N D. 16 N F ∆t = ∆ p = pfinal – pinitial = m(vfinal – vinitial) ▪ we can choose coordinate system (vectors !!!) positive left or positive right ▪ as the force is positive we want final direction to be positive, so we choose left to be positive ▪ Then F (0.2) = 0.40 [3.0 – (–5.0)] = 3.2 ▪ F = 3.2/0.2 = 16 N (positive means to the left) D

M13/TZ2 A car on a road follows a horizontal circular path at constant speed. Which of the following correctly identifies the origin and the direction of the net force on the car? Origin Direction A. car engine toward centre of circle B. car engine away from centre of circle C. friction between car tyres and road away from centre of circle D. friction between car tyres and road toward centre of circle D Newton’s first law of motion – the law of inertia ... objects in motion tend to stay in motion with the same speed and the same direction unless acted upon by a net force. Whatever the object, if it moves in a circle, there is some force acting upon it to cause it to deviate from its straight-line path, accelerate inwards and move along a circular path. For object's moving in circular motion, there is a net force acting towards the center which causes the object to seek the center.

M13/TZ2 9. The temperature of an object is −153°C. Its temperature is raised to 273°C. What is the temperature change of the object? A. 699 K B. 426 K C. 153 K D. 120 K B

M13/TZ2 10. Two ideal gases X and Y are at the same temperature. The mass of the molecules of gas X is twice the mass of the molecules of gas Y. Microscopic level: (absolute) temperature directly proportional to the average kinetic energy of the molecules of a substance: (KE)avg = 𝑘𝑇 k is Boltzmann constant B 1 2 𝑚 𝑣 2 𝑎𝑣𝑔 ~ 𝑇 1 2 𝑚 𝑥 𝑣 2 𝑥 𝑎𝑣𝑔 𝑚 𝑦 𝑣 2 𝑦 𝑎𝑣𝑔 = 𝑇 𝑇 𝑣 2 𝑥 𝑎𝑣𝑔 𝑣 2 𝑦 𝑎𝑣𝑔 = 𝑚 𝑦 𝑚 𝑥 = 1 2

M13/TZ2 11. A sample contains 4 g of helium and 20 g of neon. The mass number of helium is 4 and the mass number of neon is 20. What is the ratio number of atoms of neon number of atoms of helium ? A. 0.2 B. 1 C. 5 D. 80 B Avogadro’s number: Number of constituent particles (atoms/molecules) per mole of a given substance is 6.022×1023 mol−1

M13/TZ2 12. Which graph shows how velocity v varies with displacement x of a system moving with simple harmonic motion? A Be aware: Dependence on t: v = –  x0 sin ωt = – v0 sin ωt Dependence on x: v = ±  x 0 2 − x 2 at x = x0 & x = – x v = 0 at x = v = ±  x0 D. Is tempting. but D. is sinusoidal, it would show dependence on time not x.

M13/TZ2 13. An object undergoes simple harmonic motion with time period T and amplitude 0.5 m. At time t = 0 s the displacement of the object is a maximum. What is the displacement of the object at time t = 3𝑇 4 ? A. − 0.50 m B m C m D. 0 m Every 𝑇 4 oscillator covers distance of one amplitude D

M13/TZ2 14. Light of wavelength 600 nm travels from air to glass at normal incidence. The refractive index of the glass is 1.5. The speed of light in air is c. Which of the following correctly identifies the speed of the waves and their wavelength in the glass? 𝑛= 𝑐 𝑣 → 𝑣= 𝑐 𝑛 = 2𝑐 3 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑑𝑜𝑒𝑠 𝑛 ′ 𝑡 𝑐ℎ𝑎𝑛𝑔𝑒 𝑤ℎ𝑒𝑛 𝑤𝑎𝑣𝑒 𝑐ℎ𝑎𝑛𝑔𝑒𝑠 𝑚𝑒𝑑𝑖𝑢𝑚 𝑐=𝑛𝑣 𝑓 λ 𝑎𝑖𝑟 =𝑛𝑓 λ 𝑔𝑙𝑎𝑠𝑠 λ 𝑔𝑙𝑎𝑠𝑠 = λ 𝑎𝑖𝑟 /𝑛 D

M13/TZ2 15. Which of the following correctly describes the direction of a ray drawn relative to a wavefront for longitudinal and transverse waves? Longitudinal wave Transverse wave A parallel parallel B parallel perpendicular C perpendicular parallel D perpendicular perpendicular D

M13/TZ2 𝑅=𝜌 𝐿 𝐴 =𝜌 𝐿/2 𝐴 𝑛𝑒𝑤 → 𝐴=2 𝐴 𝑛𝑒𝑤 C
𝑅=𝜌 𝐿 𝐴 =𝜌 𝐿/2 𝐴 𝑛𝑒𝑤 → 𝐴=2 𝐴 𝑛𝑒𝑤 C 𝑟 2 =2 𝑟 2 𝑛𝑒𝑤 → 𝑟 𝑛𝑒𝑤 =𝑟/ 2

M13/TZ2 𝑅 𝑇𝑂𝑇 =𝑅+ 𝑅 2 = 3 2 𝑅 𝐼= 𝜀 𝑅 𝑇𝑂𝑇 B

18. A proton is accelerated from rest through a potential difference of 1000 V. What is the
potential difference through which an alpha particle must be accelerated to gain the same kinetic energy as the accelerated proton? A V B V C. 500 V D. 250 V M13/TZ2 ∆𝑈=𝑞∆𝑉=∆𝐾𝐸 𝑞 𝑝𝑟𝑜𝑡𝑜𝑛 ∆𝑉 𝑝𝑟𝑜𝑡𝑜𝑛 = 𝑞 𝑎𝑙𝑝ℎ𝑎 ∆𝑉 𝑎𝑙𝑝ℎ𝑎 C 19. The magnitude of the gravitational field strength at the surface of a planet of mass M and radius R is g. What is the magnitude of the gravitational field strength at the surface of a planet of mass 2M and radius 2R? A. 𝑔 4 B. 𝑔 2 C. g D. 2g Force between planet (mass M) and object of mass m is weight of that object. So 𝑚𝑔=𝐺 𝑀𝑚 𝑅 2 R – distance between center of the planet and object m = radius of the planet. 𝑔=𝐺 𝑀 𝑅 → 𝑔 𝑛𝑒𝑤 =𝐺 2𝑀 (2𝑅) 2 = 𝑔 2 B

20. Three positive point charges +Q are fixed in position at the vertices of an isosceles
triangle. P is the mid point between two of the charges. M13/TZ2 The only electric field that survives at point P is the one due to charge at the right angle corner. The other two cancel each other out. Which arrow correctly identifies the direction of the electric field at point P? A. W B. X C. Y D. Z B

M13/TZ2 21. Three wires, P, Q and R, carry equal currents directed into the plane of the paper. Currents in same direction attract! Currents in opposite direction repel! Which arrow correctly identifies the direction of the magnetic force on wire P? A. W B. X C. Y D. Z B

22. Which particle is acted on by both the strong nuclear force and the Coulomb force?
A. Antineutrino B. Electron C. Neutron D. Proton M13/TZ2 D 23. A nucleus of californium (Cf) contains 98 protons and 154 neutrons. Which of the following correctly identifies this nucleus of californium? C

24. Which of the following gives the particles of the same energy in an increasing order
of ionizing ability? A. β, α, γ B. α, β, γ C. γ, α, β D. γ, β, α M13/TZ2 D 25. The use of which energy source enhances the greenhouse effect the most? A. Wood B. Coal C. Wind D. Tidal B

26. The volume expansion coefficient of water is γ
26. The volume expansion coefficient of water is γ . The average depth of the ocean is h. What is the expected fractional increase ∆ℎ ℎ in the sea level for a temperature increase of Δθ ? A. γ Δθ h B. γ Δθ C. γ h Δθ D. γ Δθ M13/TZ2 𝛾= ∆𝑉 𝑉 0 ∆𝜃 (K−1 or oC−1) γ-coefficient of volume expansion ∆𝜃 increase in temp. coefficient of volume expansion = change in volume per unit volume per degree 𝛾= 𝑙𝑒𝑛𝑔𝑡ℎ×𝑤𝑖𝑑𝑡ℎ×∆ℎ (𝑙𝑒𝑛𝑔𝑡ℎ×𝑤𝑖𝑑𝑡ℎ×ℎ) ∆𝜃 = ∆ℎ ℎ∆𝜃 B

M13/TZ2 27. Which of the following correctly describes the energy transformation within photovoltaic cells and within solar heating panels? Photovoltaic cells Solar heating panels A. solar to thermal solar to electrical B. solar to thermal solar to thermal C. solar to electrical solar to electrical D. solar to electrical solar to thermal D

M13/TZ2 28. An oscillating water column (OWC) ocean-wave converter produces a power P. What is the power output of this converter if the amplitude and speed of the waves are both doubled? A. 2P B. 4P C. 8P D. 16P Wave power: P/L A - amplitude of the wave, L - length of wavefront  - density of water C

M13/TZ2 29. The graph shows the spectrum of a black-body.
Which graph shows the spectrum of a body of emissivity 0.5 at the same temperature as the black-body? (The original graph is shown dotted.) C

M13/TZ2 30. A student states that the following factors may lead to global warming I. decreased albedo of the Earth’s surface II. increase in volcanic activity III. deforestation. Which of the above statements are correct? A. I and II only B. II and III only C. I and III only D. I, II and III D

N13/4/PHYSI/SPM/ENG/NOV/XX
Physics Standard level Paper 1 Wednesday 6 November 2013 (morning) 45 minutes

N13/NOV 1. The sides of a square are measured to be 5.0 ± 0.2 cm. Which of the following gives the area of the square and its uncertainty? A ± 0.2 cm2 B ± 0.4 cm2 C. 25 ± 2 cm2 D. 25 ± 4 cm2 𝑎𝑟𝑒𝑎= 𝑎 2 =25 𝑐𝑚 2 (2𝑆𝐹) C ∆𝑎𝑟𝑒𝑎 𝑎𝑟𝑒𝑎 = ∆𝑎 𝑎 + ∆𝑎 𝑎 =2 ∆𝑎 𝑎 ∆𝑎𝑟𝑒𝑎=2𝑎∆𝑎= 𝑐𝑚 2 =2 𝑐𝑚 2 Uncertainties are rounded to one digit 2. Which of the following lists two vector quantities and one scalar quantity? A. force, mass, time B. acceleration, energy, momentum C. distance, impulse, power D. density, pressure, temperature B

N13/NOV 3. A tennis ball is dropped from the top of a high building. Air resistance cannot be neglected. Which graph represents the variation with time t of the magnitude of the acceleration a of the ball before it hits the ground? B

N13/NOV Terminal speed – When air resistance is taken into account object in free fall will not accelerate forever. Air resistance depends on the speed of the object. As speed increases, so does air resistance until it reaches the value equal to the weight of the object. At that time net force is zero, so is acceleration. The speed doesn’t change any more. It is constant speed.

N13/NOV 4. A model plane flies with constant velocity at constant height. Which diagram represents the forces acting on the plane? D Object is in translational equilibrium if velocity is const.

5. The net force on a body is F. The impulse of F is equal to the
A. change in momentum of the body. B. rate of change of momentum of the body. C. change of kinetic energy of the body. D. change of total energy of the body. N13/NOV A Impulse is defined as the product of the net force acting on an object and time interval of action: FΔt vector! (Ns) Impulse F∆t acting on an object will produce the change of its momentum Δp: F∆t = ∆p Δp = mv - mu Ns = kg m/s Newton’s second law::

N13/NOV 6. In an inelastic collision
A. momentum and kinetic energy are both conserved. B. momentum is conserved but kinetic energy is not. C. kinetic energy is conserved but momentum is not. D. neither momentum nor kinetic energy are conserved. B

N13/NOV 7. A force which increases uniformly from 0 to a maximum value of F is applied to an object. The object does not move until the force exceeds 0.5F. As the force increases from 0.5F to F the object moves a distance x in the direction of the force. What is the work done by this force? A. 0.25Fx B. 0.5Fx C. 0.75Fx D. Fx force F 0.5 F x C distance Work is the area under F vs distance graph

Speed is constant and is circumference/period
N13/NOV 8. A body moves with uniform speed around a circle of radius r. The period of the motion is T. What is the speed of the body? A 𝑣𝑒𝑐𝑜𝑐𝑖𝑡𝑦 𝑖𝑠 𝑡𝑎𝑛𝑔𝑒𝑛𝑡𝑖𝑎𝑙 𝑡𝑜 𝑡ℎ𝑒 𝑐𝑖𝑟𝑐𝑙𝑒 Average velocity is zero, because displacement is zero Speed is constant and is circumference/period

N13/NOV 9. Molar mass is defined as
A. the number of particles in one mole of a substance. B. 1/12 the mass of one atom of carbon-12. C. the mass of one mole of a substance. D. the number of particles in 1/12 of a mole of carbon-12. C 10. Which of the following is true about boiling and evaporation? Boiling Evaporation A. occurs throughout liquid occurs at liquid surface B. occurs throughout liquid occurs throughout liquid C. occurs at liquid surface occurs at liquid surface D. occurs at liquid surface occurs throughout liquid A

N13/NOV 11. A solid of mass m is initially at temperature ΔT below its melting point. The solid has specific heat capacity c and specific latent heat of fusion L. How much thermal energy must be transferred to the solid in order to melt it completely? A. mL + mc B. mc + mLΔT C. mcΔT + LΔT D. mcΔT + mL To bring solid to melting point Q = mc∆T is needed. And then Q = mL is needed to melt it D

N13/NOV 12. For a body undergoing simple harmonic motion the velocity and acceleration are A. always in the same direction. B. always in opposite directions. C. in the same direction for a quarter of the period. D. in the same direction for half the period. D

N13/NOV 13. Which graph of displacement x against time t represents the motion of a critically damped body? A Critical/heavy damping: occurs if the resistive force is so big that the system returns to its equilibrium position without passing through it. The mass comes to rest at its equilibrium position without oscillating. The friction forces acting are such that they prevent oscillations.

N13/NOV 14. Which of the following correctly relates the direction of oscillation of the particles in a medium to the direction of energy propagation for transverse and longitudinal waves? Transverse wave Longitudinal wave A. perpendicular perpendicular B. perpendicular parallel C. parallel perpendicular D. parallel parallel B

15. Which of the following relates the amplitude A of a travelling wave to the intensity I ?
N13/NOV 𝐼= 𝑃 4𝜋 𝑑 𝑑 𝑖𝑠 𝑡ℎ𝑒 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑓𝑟𝑜𝑚 𝑡ℎ𝑒 𝑠𝑜𝑢𝑟𝑐𝑒 𝑜𝑓 𝑝𝑜𝑤𝑒𝑟 𝑎𝑝𝑝𝑎𝑟𝑒𝑛𝑡 𝑏𝑟𝑖𝑔ℎ𝑡𝑛𝑒𝑠𝑠:𝑏= 𝐿 4𝜋 𝑑 2 C 𝐸~ 𝐴 𝑎𝑛𝑑 𝐸= 𝑃 𝑡 → 𝐼~ 𝐴 2 16. Two identical waves of wavelength λ leave two sources in phase. The waves meet and superpose after travelling different distances. Which path difference will result in destructive interference? B

17. A resistor X of resistance R is made of wire of length L and
cross-sectional area A. Resistor Y is made of the same material but has a length 4L and a cross-sectional area 2A. X and Y are connected in series. What is the total resistance of the combination? A. 1.5R B. 2R C. 3R D. 9R N13/NOV 𝑅 𝑇𝑂𝑇 =𝜌 𝐿 𝐴 +𝜌 4𝐿 2𝐴 𝑅+2𝑅 C

If intensity of light decreases, RL increases, and VOUT increases
N13/NOV 18. A light dependent resistor L is connected in series with a cell C and a fixed resistor R. The cell has a negligible internal resistance. VOUT is the output voltage across L. A photoresistor or light-dependent resistor (LDR) or photocell is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photoresistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits. 𝑉 𝑂𝑈𝑇 =𝐼 𝑅 𝐿 = 𝑒𝑚𝑓 𝑅+ 𝑅 𝐿 𝑅 𝐿 = 𝑒𝑚𝑓 𝑅 𝑅 𝐿 +1 If intensity of light decreases, RL increases, and VOUT increases Which change will increase VOUT? A. Connect another resistor in parallel with L B. Decrease the intensity of light on L C. Increase the resistance of R D. Decrease the emf of C B

N13/NOV 19. Each of the resistors in the circuit has a resistance of 2.0 Ω. The cell has an emf of 3.0 V and negligible internal resistance. The ammeter has negligible resistance. 1/RTOT = 1/R + 1/3R = 4/3R RTOT = 3/2 Ω I = emf/RTOT = 2 A Current through one resistor I1 Current through three resistors I3 2 = I1 + I3 R I1 = 3R I3 I1 = 3I3 I3 = 0.5 A I1 = 1.5 A What is the ammeter reading? A. 0.4 A B. 0.5 A C. 1.5 A D. 2.0 A C

N13/NOV 20. Which diagram represents the pattern of electric field lines of two small positive point charges held at the positions shown? B

N13/NOV 21. The force F between particles in gravitational and electric fields is related to the separation r of the particles by an equation of the form 𝐹=𝑎 𝑏𝑐 𝑟 2 Which of the following identifies the units for the quantities a, b and c for a gravitational field? a b and c A. N m2 C–2 C B. N m2 C–2 kg C. N m2 kg–2 C D. N m2 kg–2 kg Both A and D will result in the product (abc) = N m2 , but the problem asks about gravitational force, not electric one. D

22. An electron of mass me and charge e accelerates between two plates separated by
a distance s in a vacuum. The potential difference between the plates is V. N13/NOV 𝑑𝑒𝑓𝑖𝑛𝑖𝑡𝑖𝑜𝑛 𝑜𝑓 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐 𝑓𝑖𝑒𝑙𝑑: 𝐸= 𝐹 𝑞 𝐸 =𝑁/𝐶 𝐸= ∆𝑉 𝑠 𝐸 = 𝑉 𝑚 𝒄𝒐𝒏𝒔𝒕. 𝑬 What is the acceleration of the electron? 𝑎= 𝐹 𝑚 𝑒 = 𝑒𝐸 𝑚 𝑒 = 𝑒 𝑉−0 𝑠 𝑚 𝑒 = 𝑒𝑉 𝑚 𝑒 𝑠 C

N13/NOV 23. In a particular atom, the nucleon number is the total number of A. protons. B. neutrons. C. electrons. D. protons and neutrons. D 24. For which quantity can the unit MeV c–2 be used? A. Mass B. Momentum C. Kinetic energy D. Binding energy A 𝐸=𝑚 𝑐 2 𝑚= 𝐸 𝑐 2 Unit for mass is unit for energy (MeV) divided by c2

N13/NOV 25. Uranium-238 forms a nucleus of plutonium-239
as a result of A. electron capture followed by alpha decay. B. electron capture followed by beta decay. C. neutron capture followed by alpha decay. D. neutron capture followed by two beta decays. D 2 protons more means 2 neutrons into 2 protons and two electrons = two beta decays : n → 1 1 p + −1 0 e β − + ν That would leave the same number of nucleons, so one extra neutron must be captured

N13/NOV 26. In the production of electric power, an advantage of using photovoltaic cells rather than fossil fuels is that the photovoltaic cells A. can be effective in any location. B. can be used continuously. C. have low initial set-up costs. D. are more environmentally friendly when in use. D

N13/NOV 27. What is the main role of the control rods and the main role of the moderator in a thermal fission reactor? Control Rods Moderator A. decrease neutron speed decrease neutron speed B. decrease neutron speed absorb neutrons C. absorb neutrons decrease neutron speed D. absorb neutrons absorb neutrons C Main energy transformations in a nuclear power station: nuclear energy → thermal energy → mechanical energy → electrical energy Three important components in the design of all nuclear reactors are moderator, control rods and heat exchanger. ▪ Moderator is a medium that slows down fast neutrons to make them suitable for reaction (water, graphite, heavy water). ▪ Control rods are movable rods that readily absorb neutrons. They can be introduced or removed from reaction chamber in order to control the rate of fission of uranium and plutonium. Made of chemical elements capable of absorbing many neutrons without fissioning themselves (cadmium, hafnium, boron, etc) ▪ Heat exchanger is used to seal off the place where nuclear reactions take place from the rest of the environment. In some nuclear power plants, the steam from the reactor goes through a heat exchanger to convert another loop of water to steam, which drives the turbine. The advantage to this design is that the radioactive water/steam never contacts the turbine.

N13/NOV 28. An oscillating water column (OWC) ocean-wave energy converter uses waves to alter the air pressure in a chamber. Which energy resources must have been involved for this method to generate electricity? I. Tides II. Wind III. Solar A. I only B. II only C. I and II only D. II and III only It is wave not tide !!!! D

N13/NOV 29. The surface temperature of a black-body emitter is doubled. By what factor does the power emitted by the body increase? A. 32 B. 16 C. 4 D. 2 B 𝑃=𝜎𝐴 𝑇 𝑖𝑛 𝑎𝑠𝑡𝑟𝑜𝑝ℎ𝑦𝑠𝑖𝑐𝑠=𝑙𝑢𝑚𝑖𝑛𝑜𝑠𝑖𝑡𝑦 30. Which option is not a possible solution to reduce the enhanced greenhouse effect? A. Decommission nuclear power plants B. Replace the use of coal and oil with natural gas C. Use combined heating and power systems (CHP) D. Use hybrid motor vehicles A