UNIVRSITY NTRN XMINTION 2017 PHYSIS uration : 2 hours Please read the following instructions carefully. 1. This paper is made up of 50 Multiple-hoice questions and comprises IGHTN (18) printed pages. 2. o not write on the question paper. 3. nswer all questions and indicate your answers on the answer sheet provided. Marks will not be deducted for wrong answers. 4. o not take any paper, including the question paper or unused answer sheets, out of the examination hall. SMPL U 2017 PHY / 03 1
USFUL INFORMTION: cceleration due to gravity, g 9.80 m s 2 vogadro s number, N 6.022 10 23 particles mol Universal gas constant, R 8.314 J K 1 mol 1 Gravitational constant, G 6.673 10 11 N m 2 kg 2 oulomb constant, k 8.99 10 9 N m 2 2 Magnitude of charge of electron, e 1.602 10 19 Mass of electron, m e 9.109 10 31 kg Mass of proton, m p 1.673 10 27 kg Mass of neutron, m n 1.675 10 27 kg Speed of light, c 2.998 10 8 m s 1 Planck s constant, h 6.626 10 34 J s tomic mass unit, u 1.661 10 27 kg SMPL U 2017 PHY / 03 2
Multiple-hoice Questions nswer all questions in this section. 1. What is the SI unit for the weight of a person? kg N kgn SI UNIT 2. The readable area of a (ompact isc) is from 2.5 cm to 6.0 cm from the center of the. In order to read the properly, the must be read at a constant speed of 1.3 ms -1. Which of the following frequencies (in revolution per minute, rpm) of rotation is not suitable for reading the? 230 rpm 250 rpm 350 rpm 450 rpm 550 rpm 3. force was applied on a ball causing its velocity to change. Its final velocity is vertically downwards. The change in velocity was horizontally to the right. SMPL Which of the following vectors best represents the possible initial velocity of the ball? 4. Which displacement-time graph best represents the motion of a falling object, where the initial acceleration of the object eventually reduces until it begins to travel at constant terminal velocity? U 2017 PHY / 03 3
None of the above 5. car is accelerated from rest by a constant force. It also experiences a drag force proportional to its speed. Which graph possibly represents the variation of the acceleration of the car with time? SMPL None of the above U 2017 PHY / 03 4
6. 3 kg mass is thrown vertically upward with an initial speed of 9.8 m/s. What is the maximum height this object will reach if the air friction is negligible? 1.00 m 4.90 m 9.80 m 19.6 m 26.2 m 7. n astronaut in a space capsule orbiting the arth appears to float inside the capsule. Which of the following statements explains this? The astronaut has zero weight. The centripetal acceleration of the astronaut and the capsule are the same. The centripetal force on the astronaut and the capsule are the same. The force of gravity on the astronaut is zero. None of the above. 8. 65.0 kg astronaut weighs 637 N at the surface of arth. What is the mass of the astronaut at the surface of the Moon, where the acceleration due to gravity is only 1.62 m/s 2? 10.7 kg 65.0 kg 105 N 637 N None of the above SMPL 9. s a 500 N basketball player jumps from the floor up toward the basket, the magnitude of the force of her feet on the floor is 1000 N. s she jumps, the magnitude of the force of the floor on her feet is 500 N 1000 N 1500 N 5000 N 5500 N 10. girl of mass m sits in a ferris wheel of radius r rotating with a constant angular speed. What is the largest variation in the apparent weight of the girl in one complete rotation of the ferris wheel? zero mg 2 mg 2 mr 2 2mr U 2017 PHY / 03 5
11. Which of the following statements about geostationary satellites is correct? Geostationary satellites must orbit from east to west. The orbital radius of a geostationary satellite can be varied as long as its period is 24 hours. It is a constellation of at least two satellites. ny geostationary satellites are not able to view the north and south poles. The mass of a geostationary satellite does not have to be fixed. 12. car driver adjusts the pressure on a car s brakes so that the car travels at constant speed down a hill from P to Q. Which statement is correct? The change in kinetic energy of the car is larger than the change in potential energy of the car. The change in kinetic energy of the car is equal to the change in potential energy of the car. The change in potential energy of the car is larger than the change in kinetic energy of the car, and they are non-zero. The change in kinetic energy of the car is zero. None of the above is correct. SMPL 13. ball is thrown vertically upwards. Neglecting air resistance, which statement is correct? The kinetic energy of the ball is non-zero at the greatest height attained. y the principle of conservation of energy, the total energy of the ball is constant throughout its motion. y the principle of conservation of momentum, the momentum of the ball is constant throughout its motion. The potential energy of the ball increase uniformly with time during the ascent. None of the above is correct. U 2017 PHY / 03 6
14. onsider a falling raindrop undergoing constant acceleration. Which pair of quantities would yield a straight line graph when plotted to represent the motion of the raindrop? Velocity of the raindrop and its displacement isplacement of the raindrop and its time in motion Kinetic energy of the raindrop and its displacement Kinetic energy of the raindrop and its time in motion None of the above 15. 1.6 kg block slides down a plane that is inclined at 25 with the horizontal, at a constant speed of 2.0 ms -1. t what rate is the frictional force doing work on the block? -28.54 W 13.25 W -13.25 W 28.54 W 313.60 W 16. roller coaster starts from rest on a hill-top. It accelerates along a frictionless track and enters a loop-the-loop of radius 60 m as shown below. SMPL In order for the roller coaster to just remain in contact with the track when it is up-side-down at the top of the loop-the-loop, the vertical height H between its starting point and the entrance of the loop-the-loop must be 90 m 120 m 150 m 180 m 190 m U 2017 PHY / 03 7
17. Which of the following is a statement of the principle of conservation of momentum? Momentum is the product of mass and velocity In an elastic collision, momentum is constant The momentum of an isolated system is a constant The sum of kinetic energy is a constant. The force acting on a body is proportional to its rate of change of momentum 18. movable notice-board of mass 2.0 kg is placed on a smooth floor. What is the initial acceleration of the notice-board when a horizontal stream of water, travelling at speed 8.0 ms -1, strikes it at a rate of 1.0 kgs -1 for a duration of 50 s. The horizontal velocity of the water will become 0 m/s after it has struck the notice board. 0.16 ms -2 3.6 ms -2 4.0 ms -2 8.0 ms -2 9.2 m s -2 19. Two particles of identical masses are initially projected towards each other on a smooth surface with speeds u 1 and u 2 respectively. They collide elastically with each other, and their directions and speeds after the collision are shown in the figure below. SMPL Which one of the following equations cannot be applied to the collision of this system? u1 u2 v2 v1 2 2 2 2 u1 u2 v1 v2 u1 u2 v2 v1 2 2 2 2 u1 u2 v1 v2 u1 v2 u2 v1 U 2017 PHY / 03 8
20. Transfer of heat through the actual movement of molecules is conduction convection radiation both and both and 21. sound wave of frequency 550 Hz is travelling in air at a speed of 330 m s. The difference in phase between two points on the wave 0.2 m apart in the direction of travel is π 2 rad π 3 rad 2π 3 rad π 4 rad 3π 4 rad 22. The frequency of the fundamental mode of transverse vibration of a stretched wire 400 mm long is 256 Hz. When the wire is lengthened to 1000 mm at the same tension, the fundamental frequency is closest to: 102 Hz 162 Hz 312 Hz 416 Hz 640 Hz SMPL 23. n organ pipe of effective length 0.34 m is closed at one end. Given that the speed of sound in air is 340 m s, the two lowest resonant frequencies are closest to: 125 Hz and 250 Hz 125 Hz and 375 Hz 250 Hz and 500 Hz 250 Hz and 750 Hz 500 Hz and 1000 Hz U 2017 PHY / 03 9
24. Two uncharged metal spheres, #1 and #2 are mounted on insulating support rods. third metal sphere #3, carrying a negative charge, is then placed near #2. Now a copper wire is momentarily connected between #1 and #2 and then removed. Finally, sphere #3 is removed. In this final state spheres #1 and #2 are still uncharged. spheres #1 and #2 both carry positive charge. spheres #1 and #2 both carry negative charge. sphere #1 carries positive charge and #2 carries negative charge. sphere #1 carries negative charge and #2 carries positive charge. 25. xperimenter uses a very small test charge q 0 and experimenter uses a test charge 2q 0 to measure an electric field produced by stationary charges. xperimenter finds a field that is greater than the field found by experimenter. the same as the field found by experimenter. less than the field found by experimenter. either greater or less than the field found by experimenter, depending on the acceleration of the test charges. either greater or less than the field found by experimenter, depending on the masses of the test charges. 26. Two isolated charges, Q and +2Q, are 2 cm apart. If F is the magnitude of the force acting on charge +2Q, what are the magnitude and direction of the force acting on charge Q? F 2, toward +2Q. 2F, away from +2Q. F, toward +2Q. F, away from +2Q. 2F, toward +2Q. SMPL 27. hollow metal sphere of radius R is positively charged. Of the following distances from the center of the sphere, which location will have the smallest electric field strength? R 2. R. 2R. 4R. None of the above because the field is of constant strength. U 2017 PHY / 03 10
28. point charge Q = 900 10 9 and two unknown point charges, q 1 and q 2, are placed as shown. The electric field at the origin O, due to charges Q, q 1 and q 2 is equal to zero. The unknown point charge q 2 is closest to +55 10 9. +95 10 9. 95 10 9. +140 10 9. 140 10 9. 29. Two conducting spheres of different radii each has charge Q. Which of the following occurs when the two spheres are connected with a conducting wire? No charge flows. Positive charge flows from the larger sphere to the smaller sphere until the electric field at the surface of each sphere is the same. Positive charge flows from the larger sphere to the smaller sphere until the electric potential of each sphere is the same. Positive charge flows from the smaller sphere to the larger sphere until the electric field at the surface of each sphere is the same. Positive charge flows from the smaller sphere to the larger sphere until the electric potential of each sphere is the same. SMPL 30. capacitor of capacitance is charged to a potential difference of 2V while a second capacitor of capacitance 2 is charged to a potential difference of V. combined capacitor is then formed by connecting the two positive plates together and the two negative plates together. What happens to this system of capacitors? oth charge and energy increase. oth charge and energy decrease. oth charge and energy remain constant. nergy decreases but charge remains constant. harge increases but energy remains constant. U 2017 PHY / 03 11
31. Two point charges, +4.0 μ and 4.0 μ, are placed as shown in the diagram. n additional charge of +2.0 μ is placed at point. The electric potential energy of this system of charges is closest to: 486 10 3 J 455 10 3 J 264 10 3 J +264 10 3 J +486 10 3 J 32. In the circuit shown, the emf of the battery is ε = 10.0 V and each of the seven capacitors has capacitance = 10.0 μ. The charge on capacitor 2 is closest to: SMPL 20.0 μ 40.0 μ 50.0 μ 60.0 μ 100.0 μ U 2017 PHY / 03 12
33. The ideal battery in the figure below gives the electric potential difference V that can appear across resistor R 1 of the circuit versus the current I in that resistor. The scale of the V axis is set by V s = 18.0 V and the scale of the I axis is set by I s = 3.00 m. Plots 2 and 3 are similar plots for resistors R 2 and R 3 respectively. The current in resistor R 2 is closest to: 0.55 m. 0.82 m. 1.36 m. 4.0 m. 6.0 m. 34. Given that ε 1 = 10 V, ε 2 = 20 V, R 1 = 10 Ω, R 2 = 20 Ω and R 3 = 40 Ω, the power delivered by the battery ε 2 is closest to: SMPL 2.5 W. 5.0 W. 10.0 W. 12.5 W. 20.0 W. U 2017 PHY / 03 13
35. velocity selector has an electric field of magnitude 2470 N directed vertically upward and a horizontal magnetic field. Positively charged particles, travelling east at a speed of 6.50 10 3 m s, enter the velocity selector and are able to pass completely through without being deflected. When a different particle with an electric charge of 4.00 10 12 enters the velocity selector travelling east, the net force acting on it is 1.90 10 9 N pointing directly downward. The speed of this particle is closest to: 2750 m s 5250 m s 7750 m s 8750 m s 9250 m s 36. small coil lies inside a large coil. The two coils are horizontal and concentric as shown. The large coil carries a constant clockwise current. The larger coil is pulled perpendicular out of the plane of the paper. Which of the following describes the direction of the induced current in the smaller coil and the resultant force between the coils? counter-clockwise, attraction. clockwise, attraction. counter-clockwise, repulsion. clockwise, repulsion. no induced current, no force. SMPL 37. The circuit shown is in a uniform magnetic field that is into the page and is increasing in magnitude at a rate of 150 T s. etermine the reading on the ammeter and the direction of current flowing through the ammeter. 0.35, downward. 0.35, upward. 0.50, upward. 0.65, upward. 0.65, downward. U 2017 PHY / 03 14
38. steady current I dissipates a certain power in a variable resistor. The resistance has to be halved to obtain the same power when a sinusoidal alternating current is used. What is the r.m.s. value of the alternating current? I 2 I 2 I 2 I 2I 39. capacitor is connected in series to an ideal a.c. power supply. The current in the capacitor lags the voltage across the capacitor by 90. leads the voltage across the capacitor by 90. is in phase with the voltage across the capacitor. leads the voltage across the capacitor by 45. lags the voltage across the capacitor by 45. 40. The wavelength of light in water is 788 nm. If the refractive index for this light in water is 1.33, the frequency of this light is closest to: 3.76 10 14 Hz 5.00 10 14 Hz 6.65 10 14 Hz 2.86 10 14 Hz 9.52 10 14 Hz SMPL 41. ray of light propagates in water (n = 1.333) and strikes a sheet of glass (n = 1.523). If the angle of refraction in the glass is 35.2, the angle of incidence is closest to: 30.3 32.8 35.2 41.2 45.0 U 2017 PHY / 03 15
42. Two thin lenses are placed 5 cm apart along the same axis and illuminated with a beam of light parallel to that axis. The first lens in the path of the beam is a converging lens of focal length 10 cm whereas the second is a diverging lens of focal length 5 cm. If the second lens is now moved towards the first, the emergent light changes from parallel to divergent changes from divergent to parallel changes from parallel to convergent changes from convergent to parallel changes from convergent to divergent 43. Two identical light waves, and, are emitted from different sources and meet at a point P. The distance from the source of to the point P is L ; and the source of is a distance L from P. Which one of the following statements is necessarily true concerning the interference of the two waves? and will interfere constructively because their amplitudes are the same. and will interfere constructively if L = L. and will interfere destructively if L L = mλ where m = 0,1,2,3, and will interfere destructively if L is not equal to L. and will interfere constructively because their wavelengths are the same. SMPL 44. iffraction occurs when light passes through a single slit. Rank the following three choices in decreasing order, according to the extent of the diffraction that occurs (largest diffraction first): I blue light, narrow slit II red light, narrow slit III blue light, wide slit Note: The blue light referred to in choices I and III is the same wavelength. lso, the narrow slit referred to in choices I and II is the same width. I, II, III II, I, III II, III, I I, III, II III, II, I U 2017 PHY / 03 16
45. grating spectrometer is used to view the spectrum of light from a helium discharge tube. The three brightest spectral lines seen are blue, red and yellow in colour. These lines appear at the positions labeled, and in the figure below though not necessarily in that order of colour. In this spectrometer, the distance between the grating and screen is 30 cm and the slit spacing in the grating is 1870 nm. The wavelength of the yellow colour spectral line is closest to: 398 nm 454 nm 565 nm 669 nm 767 nm 46. rrange the following electromagnetic waves in order of decreasing energy: visible light, X-rays, radio waves, infra-red and ultra-violet. X-rays, ultra-violet, visible light, infra-red and radio waves. X-rays, infra-red, visible light, ultra-violet and radio waves. Visible light, infra-red, ultra-violet, radio waves and X-rays. Radio waves, infra-red, visible light, ultra-violet and X-rays. Radio waves, ultra-violet, infra-red, X-rays and visible light. 47. lectrons are emitted from a certain metal with a maximum kinetic energy of 2 ev when 6-eV photons are incident on its surface. If photons of twice the frequency are incident on this metal which one of the following statements is true? SMPL No electrons will be emitted. lectrons will be emitted with a maximum kinetic energy of 2 ev. lectrons will be emitted with a maximum kinetic energy of 4 ev. lectrons will be emitted with a maximum kinetic energy of 8 ev. lectrons will be emitted with a maximum kinetic energy of 12 ev. 48. The de roglie wavelength of an electron is 1.2 10 10 m. The kinetic energy of the electron is closest to: 1.5 10 15 J 1.6 10 16 J 1.7 10 17 J 1.8 10 18 J 1.9 10 19 J U 2017 PHY / 03 17
49. stronomers observe a series of spectral lines in the light from a distant galaxy. On the hypothesis that the lines form the Lyman series for an (new?) unknown atom, they start to construct the energy-level diagram shown, which gives the wavelengths of the first four lines and the short-wavelength limit of this series. The energy of the second excited state is closest to: 8.18 ev 2.05 ev 0.91 ev 0.51 ev 0.33 ev 50. The radioactive isotope radon-222 ( 86Rn) may decay spontaneously by emitting an alpha particle. The daughter nucleus is an isotope of polonium (Po). The atomic masses of these isotopes are: 222 Rn 222 SMPL, 222.0157 u; Po, 218.00896 u; He, 4.00260 u; sample of radon-222 contains 3.0 10 7 nuclei. The total energy that will be released within a time interval of T 1 2 through alpha decay of the radon-222 is closest to: 3.856 MeV 5.785 10 7 MeV 8.677 10 7 MeV 1.012 10 8 MeV 1.085 10 8 MeV 4 N OF PPR U 2017 PHY / 03 18