AP Physics 2 Exam Review Questions

Transcription

1 Chapter 10 5) When a heavy metal block is supported by a cylindrical vertical post of radius R, it exerts a force F on the post. If the diameter of the post is increased to 2R, what force does the block now exert on the post? A) F/4 B) F/2 C) F/ D) F E) 2F 6) As shown in the figure, fluid fills a container having several sections. At which of the indicated points is the pressure greatest? A) A B) B C) C D) D E) The pressure is the same at each of the labeled points. 15) A spherical ball of lead (density 11.3 g/cm 3 ) is placed in a tub of mercury (density 13.6 g/cm 3 ). Which answer best describes the result? A) The lead ball will float with about 83% of its volume above the surface of the mercury. B) The lead ball will float with its top exactly even with the surface of the mercury. C) The lead ball will float with about 17% of its volume above the surface of the mercury. D) The lead will sink to the bottom of the mercury. 19) Salt water is denser than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the volume of water displaced in the salt water is A) more. B) less. C) the same. D) Cannot be determined because we do not know the volume of the ship. 6) A 1938 nickel has a diameter of mm, a thickness of 1.95 mm, and weighs N. What is its density? A) kg/m 3 B) kg/m 3 C) kg/m 3 D) kg/m 3 E) kg/m 3 9) The weight of a 1200-kg car is supported equally by the four tires, which are inflated to the same gauge pressure. What gauge pressure is required so the area of contact of each tire with the road is 100 cm 2? A) Pa B) Pa C) Pa D) Pa 15) The Aswan High Dam on the Nile River in Egypt is 111 m high. What is the gauge pressure in the water at the foot of the dam? The density of water is 1000 kg/m 3. A) Pa B) Pa C) Pa D) Pa E) Pa 26) A 12,000-N car is raised using a hydraulic lift, which consists of a U-tube with arms of unequal areas, filled with oil and capped at both ends with tight-fitting pistons. The wider arm of the U-tube has a radius of 18.0 cm and the narrower arm

2 has a radius of 5.00 cm. The car rests on the piston on the wider arm of the U-tube. The pistons are initially at the same level. What is the initial force that must be applied to the smaller piston in order to start lifting the car? For purposes of this problem, neglect the weight of the pistons. A) 727 N B) 926 N C) 2.90 kn D) 3.33 kn E) 1.20 kn 29) In a hydraulic garage lift, the small piston has a radius of 5.0 cm and the large piston has a radius of 15 cm. What force must be applied on the small piston in order to lift a car weighing 20,000 N on the large piston? Assume the pistons each have negligible weight. A) N B) N C) N D) N 34) An object has a volume of 4.0 m 3 and weighs 40,000 N. What will its apparent weight be in water of density 1000 kg/m 3? A) 40,000 N B) 39,200 N C) 9,800 N D) 800 N 35) A 4.0-kg cylinder of solid iron is supported by a string while submerged in water. What is the tension in the string? The density of iron is 7860 kg/m 3 and that of water is 1000 kg/m 3. A) 2.5 N B) 20 N C) 24 N D) 34 N E) 40 N 62) A pump uses a piston of 15 cm diameter that moves at 2.0 cm/s as it pushes a fluid through a pipe. What is the speed of the fluid when it enters a portion of the pipe that is 3.0 mm in diameter? Treat the fluid as ideal and incompressible. A) 50 m/s B) 50 cm/s C) 6.0 cm/s D) 22 cm/s 65) Ideal incompressible fluid flows through a 4.0-cm-diameter pipe at 1.0 m/s. There is a 2.0 cm diameter constriction in the line. What is the speed of the fluid in this constriction? A) 0.25 m/s B) 0.50 m/s C) 2.0 m/s D) 4.0 m/s 66) Water, which we can treat as ideal and incompressible, flows at 12 m/s in a horizontal pipe with a pressure of Pa. If the pipe widens to twice its original radius, what is the pressure in the wider section? A) Pa B) Pa C) Pa D) Pa Chapter 16 7) A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres? A) The sphere near the charged rod becomes positive and the other one becomes negative. B) The sphere near the charged rod becomes negative and the other one becomes positive. C) The spheres do not get any charge. D) Both spheres become negative. E) Both spheres become positive. 13) Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude F due to the other. With time, charge gradually diminishes on both spheres by leaking off. When each of the spheres has lost half its initial charge, what will be the magnitude of the electrostatic force on each one?

3 A) 1/16 F B) 1/8 F C) 1/4 F D) 1/2 F E) 1/ F 19) Four point charges Q of equal magnitude and sign are arranged on three of the corners of the square of side d as shown in the figure Which one of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square? A) A B) B C) C D) D 24) An electron is initially moving to the right when it enters a uniform electric field directed upwards, as shown in the figure. Which trajectory (X, Y, Z, or W) will the electron follow in the field? A) trajectory W B) trajectory X C) trajectory Y D) trajectory Z 25) Four tiny charged particles (two having a charge +Q and two having a charge -Q) are distributed on the x- and y-axes as shown in the figure. Each charge is equidistant from the origin. In which direction is the net electric field at the point P on the y-axis? A) directly up (in the +y direction) B) directly left (-x direction) C) upwards and towards the left D) upwards and towards the right E) The net field is zero, so there is no direction. 2) A piece of plastic has a net charge of μc. How many more protons than electrons does this piece of plastic have? (e = C) A) B) C) D) E)

4 12) A proton is located at the point (x = 1.0 nm, y = 0.0 nm) and an electron is located at the point Find the magnitude of the electrostatic force that each one exerts on the other. (k = 1/4πε0 = N m2/c2, e = C) A) N B) N C) N D) N 19) Two tiny particles having charges of μc and μc are placed along the y-axis. The µC particle is at y = 0.00 cm, and the other particle is at y = cm. Where must a third charged particle be placed along the y-axis so that it does not experience any net electric force due to the other two particles? A) m B) 2.99 m C) m D) m E) m 24) A point charge Q1 = +6.0 nc is at the point (0.30 m, 0.00 m); a charge Q2 = -1.0 nc is at (0.00 m, 0.10 m), and a charge Q3 = +5.0 nc is at (0.00 m, 0.00 m). What are the magnitude and direction of the net force on the +5.0-nC charge due to the other two charges? (k = 1/4πε0 = N m2/c2) Answer: 5.4 µn at 56 above -x-axis 36) The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads. The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1. What is the charge on each sphere? (k = 1/4πε0 = N m2/c2) A) 22 nc B) 89 nc C) 360 nc D) 180 nc E) 45 nc 42) What is the magnitude of a the vertical electric field that will balance the weight of a plastic sphere of mass that has been charged to -3.0 nc? (k = 1/4πε0 = N m2/c2) A) N/C B) N/C C) N/C D) N/C 43) An electron is placed in a uniform electric field of N/C that points to the right. (e = C, melectron = kg) (a) What are the magnitude and direction of the force on the electron? (b) If the electron is released from rest, what is its speed after 3.0 ps? Answer: (a) N to the left (b) 24 km/s 53) An electric dipole consists of charges of ±6.00 µc that are 10.0 cm apart, as shown in the figure. Find the magnitude and direction of the electric field this dipole produces at point P, which is 7.00 cm from each charge. (k = 1/4πε0 = N m2/c2) Answer: N/C, to the left parallel to the line connecting the two charges Chapter 17 27) Which of the following will increase the capacitance of a parallel-plate capacitor? (There could be more than one correct choice.) A) a decrease in the plate area and an increase in the plate separation

5 B) a decrease in the potential difference between the plates C) an increase in the potential difference between the plates D) an increase in the plate area and a decrease in the plate separation E) an increase in the charge on the plates 2) A tiny particle with charge μc is initially moving at 55 m/s. It is then accelerated through a potential difference of 500 V. How much kinetic energy does this particle gain during the period of acceleration? A) J B) J C) 100 J D) 2500 J 13) A sphere with radius 2.0 mm carries a charge. What is the potential difference, between point B, which is from the center of the sphere, and point A, which is from the center of the sphere? (k = 1/4πε0 = N m2/c2) A) 1500 V B) V C) 170 V D) V 17) Three point charges, μc, μc, and μc, are located along the x-axis as shown in the figure. What is the electric potential (relative to infinity) at point P due to these charges? (k = 1/4πε0 = N m2/c2) A) -307 kv B) +307 k V C) -154 kv D) +154 kv E) 0.00 kv 51) Two isolated copper plates, each of area 0.40 m2, carry opposite charges of magnitude C. They are placed opposite each other in parallel alignment, with a spacing of 4.0 cm between them. What is the potential difference between the plates? (ε0 = C2/N m2) A) 0.40 V B) 3.0 V C) 3.2 V D) 7.6 V E) 8.0 V 69) Each plate of an ideal air-filled parallel-plate capacitor has an area of , and the separation of the plates is An electric field of is present between the plates. What is the capacitance of this capacitor? (ε0 = C2/N m2) A) 180 pf B) 120 pf C) 300 pf D) 240 pf E) 360 pf Chapter 18 14) You are given a copper bar of dimensions 3 cm 5 cm 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the largest possible resistance, you should attach the leads to the opposite faces that measure A) 3 cm 5 cm. B) 3 cm 8 cm. C) 5 cm 8 cm. D) Any pair of faces produces the same resistance. 1) A 10-A current flows through a wire for 2.0 min. (e = C) (a) How much charge has passed through this wire? (b) How many electrons have passed any point in the wire?

6 Answer: (a) 1200 C (b) ) What is the voltage drop across a 5.0-Ω resistor if the current through it is 5.0 A? A) 100 V B) 25 V C) 4.0 V D) 1.0 V 17) A 4000-Ω resistor is connected across a 220-V power source. What current will flow through the resistor? A) A B) 1.8 A C) 5.5 A D) 18 A 18) A light bulb operating at 110 V draws 1.40 A of current. What is its resistance? A) 12.7 Ω B) 78.6 Ω C) 109 Ω D) 154 Ω 7) Suppose you have two capacitors and want to use them to store the maximum amount of energy by connecting them across a voltage source. You should connect them A) in series across the source. B) in parallel across the source. C) It doesn't matter because the stored energy is the same either way. 8) Four unequal resistors are connected in series with each other. Which one of the following statements is correct about this combination? A) The equivalent resistance is equal to that of any one of the resistors. B) The equivalent resistance is equal to average of the four resistances. C) The equivalent resistance is less than that of the smallest resistor. D) The equivalent resistance is less than that of the largest resistor. E) The equivalent resistance is more than the largest resistance. 21) A 9-V battery is hooked up to two resistors in series using wires of negligible resistance. One has a resistance of 5 Ω, and the other has a resistance of 10 Ω. Several locations along the circuit are marked with letters, as shown in the figure. Which statements about this circuit are true? (There could be more than one correct choice.) A) The current is exactly the same at points A, B, C, and D. B) The current at A is greater than the current at B, which is equal to the current at C, which is greater than the current at D. C) The current at A is greater than the current at B, which is greater than the current at C, which is greater than the current at D. D) The potential at B is equal to the potential at C. E) The potential at D is equal to the potential at C., D 29) For the circuit shown in the figure, write the Kirchhoff current equation for the node labeled A. Notice the directions of the currents! Answer: I1 - I2 + I3 = 0 30) For the circuit shown in the figure, write the Kirchhoff loop equation for the entire outside loop. Notice the directions of the currents!

7 Answer: V1 + I3R3 - V3 - I1R1 = 0 3) A network of capacitors is connected across a potential difference V0 as shown in the figure. (a) What should V0 be so that the 60.0-µF capacitor will have 18.0 µc of charge on each of its plates? (b) Under the conditions of part (a), how much total energy is stored in this network of capacitors? Answer: (a) 1.50 V (b) 13.5 μj 31) What is the equivalent resistance between points A and B of the network shown in the figure? Answer: 16 Ω 52) A circuit contains two batteries and a 2.0-Ω resistor as shown in the figure. The emfs and internal resistances of these batteries are indicated in the figure, and all numbers are accurate to two significant figures. What are the terminal voltages of (a) the 6.0-V battery and (b) the 12-V battery? Answer: (a) -1.2 V (the terminal polarity is opposite from the polarity of the internal emf) (b) 8.4 V 61) A certain 20-A circuit breaker trips when the current in it equals 20 A. What is the maximum number of 100-W light bulbs you can connect in parallel in an ideal 120-V dc circuit without tripping this circuit breaker? A) 11 B) 17 C) 23 D) 27 71) If emf of the ideal battery is V = 100 V, what is the potential difference across R5 for the circuit shown in the figure? A) 19 V B) 40 V C) 75 V D) 77 V Chapter 20 25) An electron has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component A) to the west.

8 B) to the east. C) upward. D) downward. E) to the north. 26) A proton has an initial velocity to the south but is observed to curve upward as the result of a magnetic field. This magnetic field must have a component A) to the west. B) to the east. C) upward. D) downward. E) to the north. 28) A charged particle is injected into a uniform magnetic field such that its velocity vector is perpendicular to the magnetic field lines. Ignoring the particle's weight, the particle will A) move in a straight line. B) follow a spiral path. C) move along a parabolic path. D) follow a circular path. 33) A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the poles of a magnet, as shown in the figure If there is a current I flowing through this coil in the direction shown, what is the direction of the force acting on section AB of this coil? A) perpendicular to and into the page B) perpendicular to and out of the page C) in the direction of the magnetic field D) in the opposite direction of the magnetic field E) The force is zero. 54) Two long parallel wires placed side-by-side on a horizontal table carry identical current straight toward you. From your point of view, the magnetic field at a point exactly between the two wires A) points upward. B) points downward. C) points toward you. D) points away from you. E) is zero. 63) The magnetic field at a distance of 2 cm from a long straight current-carrying wire is 4 μt. What is the magnetic field at a distance of 1 cm from this wire? A) 2 μt B) 4 μt C) 6 μt D) 8 μt E) 10 μt 1) A proton moving at m/s horizontally enters a region where a magnetic field of 0.12 T is present, directed vertically downward. What magnitude force acts on the proton due to this field? (e = C) Answer: N 7) A proton is projected with a velocity of 7.0 km/s into a magnetic field of 0.60 T perpendicular to the motion of the proton. What is the magnitude of the magnetic force that acts on the proton? (e = C) A) 0 N B) N C) N D) N E) N 17) An electron moving perpendicular to a uniform magnetic field of T moves in a circle of radius 0.40 cm. How fast is this electron moving? (e = C, melectron = kg) A) m/s

9 B) m/s C) m/s D) m/s E) m/s 25) A wire along the z-axis carries a current of 4.9 A in the +z direction. Find the magnitude and direction of the force exerted on a 3.3-cm long length of this wire by a uniform magnetic field pointing in the -x direction having a magnitude Answer: N, -y direction 28) What is the force per meter on a straight wire carrying 5.0 A when it is placed in a magnetic field of T so that the wire makes an angle of 27 with respect to the magnetic field lines. A) N/m B) N/m C) 0.17 N/m D) 0.26 N/m 43) Two long parallel wires are m apart and carry currents of 4.00 A and 6.00 A. What is the magnitude of the force per unit length that each wire exerts on the other wire? (μ0 = 4π 10-7 T m/a) A) 2.00 μn/m B) 5.00 μn/m C) 12.0 μn/m D) 16.0 μn/m E) 38.0 μn/m 70) How much current must flow through a long straight wire for the magnetic field strength to be 1.0 mt at 1.0 cm from a wire? (μ0 = 4π 10-7 T m/a) A) 50 ma B) 9.2 A C) 16 A D) 50 A E) 5.0 ma Chapter 21 18) A bar magnet is oriented above a copper ring, as shown in the figure. If the magnet is pulled upward, what is the direction of the current induced in the ring, as viewed from above? A) There is no current in the ring. B) counterclockwise C) clockwise 31) As shown in the figure, a C-shaped conductor is in a uniform magnetic field B out of the page, and this field is increasing. What is the polarity of the induced emf in terminals X and Y? A) X and Y are at the same potential. B) X is positive and Y is negative. C) Y is positive and X is negative. 2) A flat circular loop of radius 0.10 m is rotating in a uniform magnetic field of 0.20 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are perpendicular. A) 0 T m2 B) T m2 C) T m2 D) T m2 10) A flat circular coil having 16 turns, each of diameter 20 cm, is in a uniform and steady 0.13-T magnetic field.

10 (a) Find the total magnetic flux through the coil when the field is perpendicular to the plane of the coil. (b) If the coil is rotated in 10 ms so its plane is parallel to the field, find the average induced emf in the coil. Answer: (a) T m2 (b) 6.5 V 29) As shown in the figure, a region of space contains a uniform magnetic field. The magnitude of this field is 2.8 T, and it is directed straight into the plane of the page in the region shown. Outside this region the magnetic field is zero. A rectangular loop measuring 0.20 m by 0.60 m and having a resistance of 2 Ω is being pulled into the magnetic field by an external force, as shown. (a) What is the direction (clockwise or counterclockwise) of the current induced in the loop? (b) Calculate the magnitude of the external force Fext that is required to move the loop at a constant speed of 3.9 m/s. Answer: (a) counterclockwise (b) N Chapter 23 19) The focal length of a convex mirror is has a magnitude of 20 cm. What is its radius of curvature? A) -10 cm B) 40 cm C) -40 cm D) -20 cm E) 20 cm 25) A convex mirror has a focal length of magnitude f. An object is placed in front of this mirror at a point f from the face of the mirror. The image will appear A) behind the mirror. B) upright and reduced. C) upright and enlarged. D) inverted and reduced. E) inverted and enlarged. 36) A thin lens projects an image of a man as shown in the figure. Rays marked A, B, and C travel to the lens from the man's ear. Draw the paths of these three rays after they have passed through the lens. Note that A is parallel to the principal axis, B goes through the center of the lens, C goes through the focal point on the left, and the point marked f is the focal point on the right of the lens. Answer: 47) Which of following statements about the image formed by a single diverging lens are true? (There could be more than one correct choice.) A) The image is always real. B) The image is always virtual. C) The image is always inverted. D) The image is always upright. E) The image is always smaller than the object., D 4) A thin laser beam traveling in air strikes the surface of a glass plate at 41.2 with the normal. In the plate, this beam makes an angle of 22.4 with the normal. What is the speed of light in this glass?(c = m/s) Answer: m/s

11 18) As shown in the figure, a laser positioned on a ship is used to communicate with a small research submarine resting on the bottom of a lake. The laser is positioned 12 m above the surface of the water, and it strikes the water 20 m from the side of the ship. The water is 58 m deep and has an index of refraction of How far horizontally is the submarine from the side of the ship? (Assume all numbers are accurate to three significant figures.) A) 69 m B) 49 m C) 89 m D) 59 m E) 79 m 33) During the investigation of a new type of optical fiber having an index of refraction a laser beam is aimed at the flat end of a straight fiber, as shown in the figure. What is the maximum angle of incidence θ1 if the beam is not to escape from the sides of the fiber if it is surrounded by air? A) 42.9 B) 39.8 C) 36.7 D) 33.6 E) ) An object is placed 50 cm in front of a concave mirror with a focal length of 25 cm. What is the magnification produced by the mirror? A) B) -1.0 C) +1.5 D) -2.0 E) ) An object that is 10.0 cm tall is placed 37.0 cm in front of a concave mirror of focal length 18.5 cm. How tall is the image? A) 2.5 cm B) 5.0 cm C) 7.5 cm D) 20.0 cm E) 10.0 cm 71) A convex spherical mirror has a focal length of magnitude 20 cm. If an object is placed 10 cm in front of the mirror on the mirror's axis, where is the image located? A) 20 cm behind the mirror B) 20 cm in front of the mirror C) 6.7 cm behind the mirror D) 6.7 cm in front of the mirror 91) A lab specimen is 15.2 mm from a converging lens. The image is 4.0 mm tall and 9.0 cm from the lens. How tall is the specimen? A) 6.8 mm B) 5.4 mm C) 1.7 mm D) 0.68 mm 92) A wrench is placed at 30 cm in front of a diverging lens with a focal length of magnitude 10 cm. What is the magnification of the wrench? A) 0.25 B) C) 0.67

12 D) E) 4.0 Chapter 24 31) A double-slit experiment uses coherent light of wavelength 633 nm with a slit separation of mm and a screen placed 2.0 m away. (a) How wide on the screen is the central bright fringe? (b) What is the distance on the screen between first-order and second-order bright fringes? (c) What is the angular separation (in radians) between the central maximum and the first-order maximum? Answer: (a) 1.3 cm (b) 1.3 cm (c) 6.33 mrad 32) In a two-slit experiment, monochromatic coherent light of wavelength 600 nm passes through a pair of slits separated by 2.20 x m. At what angle away from the centerline does the first bright fringe occur? A) 1.56 B) 2.22 C) 3.12 D) 4.70 E) 6.24 Chapter 27 14) How much energy is carried by a photon of light having frequency 110 GHz? (h = J s) A) J B) J C) J D) J 15) What frequency of electromagnetic radiation has photons of energy J? (h = J s) A) 710 khz B) 4.7 MHz C) 710 MHz D) 1.4 GHz 27) A photoelectric surface has a work function of 2.10 ev. Calculate the maximum kinetic energy, in ev, of electrons ejected from this surface by electromagnetic radiation of wavelength 356 nm. (1 ev = J, c = m/s, h = J s) Answer: 1.39 ev 28) If the longest wavelength of light that is able to dislodge electrons from a metal is 373 nm, what is the work function of that metal, in electron-volts? (1 ev = J, c = m/s, h = J s) Answer: 3.33 ev Var: 1 Chapter 30 13) The symbol for a certain isotope of strontium is Sr. What is the mass number of this isotope? A) 38 B) 52 C) 88 D) 90 E) ) What is true of an element of atomic number 15 that has an isotope of mass number 32? (There could be more than one correct choice.) A) the number of protons in the nucleus is 15. B) the number of neutrons in the nucleus is 15. C) the number of protons in the nucleus is 32. D) the number of nucleons in the nucleus is 47. E) the number of neutrons in the nucleus is 17., E 26) An α particle is also known as A) an electron. B) a positron. C) a helium nucleus. D) a high-energy photon.

13 27) A β- particle is also known as A) an electron. B) a positron. C) a helium nucleus. D) a high-energy photon. 28) A β+ particle is also known as A) an electron. B) a positron. C) a helium nucleus. D) a high-energy photon. 29) A gamma ray is also known as A) an electron. B) a positron. C) a helium nucleus. D) a high-energy photon. 43) A radioactive isotope of atomic number Z emits an alpha particle, and the daughter nucleus then emits a beta-minus particle. What is the atomic number of the resulting nucleus? A) Z -1 B) Z + 1 C) Z - 2 D) Z ) A radioactive isotope of atomic number Z emits a beta-minus particle, and then the daughter nucleus emits a gamma ray. What is the atomic number of the resulting nucleus after both processes? A) Z - 1 B) Z + 1 C) Z - 2 D) Z ) Polonium-216 decays to lead-212 by emitting what kind of nuclear radiation? A) alpha B) beta-minus C) beta-plus D) gamma E) x-rays. 46) The atom Fr decays to Ra by emitting what kind of nuclear radiation? A) alpha B) beta-minus C) beta-plus D) gamma E) x-rays.