physics 2 practice exams 2017, 2018, 2019 mcq
A plutonium nucleus of mass M is at rest when it spontaneously emits a high-energy photon of frequency f. After the decay, the photon moves off in one direction and the nucleus recoils with speed v in the opposite direction. The nucleus' mass decreases by an amount ∆m . Which of the following equations correctly represents the conservation of energy in the decay? A (∆m)c^2 = ½(M-∆m)v^2 + hf B (∆m)c^2 = ½(M-∆m)v^2 - hf C Mc^2 = ½(M-∆m)v^2 + hf D Mc^2 = ½(M-∆m)v^2 - hf
A
A sample of gas has a temperature of 200 K. If the speed of every gas molecule in the sample is doubled, what is the new temperature of the gas? A 800 K B 400 K C 200 K D 100 K
A
Conducting rod A will be given a positive charge in a procedure that uses some or all of the following steps in an appropriate order. Step W: Rod A is connected to ground. Step X: Negatively charged rod B is brought near, but does not touch, rod A. Step Y: The connection between ground and rod A is removed. Step Z: Rod B is moved away. Which of the following lists sufficient steps in an order that will give rod A a positive charge? Select two answers. A W, X, Y B W, X, Z C W, X, Y, Z D W, X, Z, Y
A, C
A capacitor initially has only air between its plates. The charge on the capacitor as a function of applied potential difference is measured, and the results are shown in graph 1 above. The capacitor is discharged, a dielectric material is inserted between the plates, and the charge as a function of applied potential difference is measured again. The results are shown in graph 2. Which of the following is equal to the dielectric constant of the material inserted into the capacitor? A The slope of graph 1 divided by the slope of graph 2 B The slope of graph 2 divided by the slope of graph 1 C The vertical intercept of graph 1 divided by the vertical intercept of graph 2 D The vertical intercept of graph 2 divided by the vertical intercept of graph 1
B
A positively charged particle is moving horizontally when it enters the uniform electric field between two parallel charged plates, as shown in the figure above. Which of the following correctly shows the x- and y-components of the velocity v as a function of time t ? A vx straight horizontal, vy straight horizontal B vx straight horizontal, vy linear down starting at 0 C vx straight horizontal, vy linear down starting same as vx D vx linear down starting at 0, vy straight horizontal
B
A proton and an electron are held a short distance apart and released from rest. The only nonnegligible forces on the particles are the electrostatic forces they exert on each other. Which of the following statements is true? A The magnitude of the electrostatic force exerted on the proton by the electron is greater than that exerted on the electron by the proton. B The magnitude of the acceleration of the proton is less than the magnitude of the acceleration of the electron. C The proton must move a larger distance to have the same magnitude change in potential energy as the electron. D The proton must move the same distance to have the same change in speed as the electron.
B
A student is comparing three lenses of the same size and shape that are made of different materials. A small object, represented by the thick black arrow, is held on one side of each lens. The ray diagrams above show the formation of the image, represented by the gray arrow, for each lens. Which of the following correctly ranks the index of refraction n of the lenses? A n1 > n2 > n3 B n2 > n1 > n3 C n3 > n1 > n2 D n3 > n2 > n1
B
Some students observe that a hollow metal sphere hanging on an insulating string is attracted to a positively charged rod. They decide that this is evidence that the sphere could also be charged. The answer to which of the following questions might determine whether they are correct? A Is the sphere still attracted when the positively charged rod is placed on the other side of the sphere? B Is the sphere repelled by a negatively charged rod? C Is the attraction of the sphere to the rod weaker when the distance between them is increased? D Is the attraction of the sphere to the rod stronger when the charge on the rod is doubled?
B
The figure above shows a small compass C that is equidistant from the poles of two identical bar magnets. Which of the following best represents the direction that the needle of the compass will point? A north on top south on bottom, leaning to the left B south on top north on bottom, leaning to the left C south on top north on bottom, leaning to the right D north on top south on bottom, leaning to the right
B
Directions: For the question or incomplete statement below, two of the suggested answers are correct. For this question, you must select both correct choices to earn credit. No partial credit will be earned if only one correct choice is selected. Select the two that are best in each case. A student is given a sample of gas that is at room temperature and is sealed in a container by a movable piston. Which of the following adjustments would allow the student to increase the pressure of the gas? Select two answers. A Put the container in a tank of room-temperature water and pull the piston outward. B Put the container in a tank of room-temperature water and push the piston inward. C Put the container in a tank of hot water and hold the piston in place. D Put the container in a tank of cold water and hold the piston in place.
B, C
A capacitor with capacitance C0 has a charge Q0. It is then connected in a circuit with a switch and an initially uncharged capacitor with capacitance C0 / 3 , as shown in the figure above. What are the final charges on the capacitors a long time after the switch is closed? A Charge on C0 Charge on C0 / 3 Q0/2 Q0/2 B Charge on C0 Charge on C0 / 3 Q0/3 2Q0/3 C Charge on C0 Charge on C0 / 3 3Q0/4 Q0/4 D Charge on C0 Charge on C0 / 3 2Q0/3 Q0/3
C
A closed chamber filled with a gas that is modeled as ideal has a movable piston of area A. The graph above of pressure P as a function of volume V shows three processes that make up cycle XYZX through which the gas is taken. Process ZX is isothermal. During which process is the amount of work done on the gas equal to the amount of energy that the gas exchanges with its surroundings through heating or cooling? A XY B YZ C ZX D None of the processes; the amount of work done on the gas is always greater than the amount of energy that the gas exchanges with its surroundings through heating or cooling.
C
A closed chamber filled with a gas that is modeled as ideal has a movable piston of area A. The graph above of pressure P as a function of volume V shows three processes that make up cycle XYZX through which the gas is taken. Process ZX is isothermal. What is the force exerted on the piston by the gas during process XY ? A P1V1 B P1V1 /2 C P1A D P1A /2
C
A small, well-insulated building is kept cool on a hot day. A person in the building holds a hand close to, but not touching, a solid metal door to the outside and feels warmth coming from the metal door. Which statement best describes how most of the energy is transferred from the outside to the person's hand? A Thermal energy from the outside is convected through the metal door. Thermal energy from the door is conducted by the air and is detected by the person's hand. B Thermal energy from the outside is convected through the metal door. The door radiates energy that is detected by the person's hand. C Thermal energy from the outside is conducted through the metal door. The door radiates energy that is detected by the person's hand. D Thermal energy from the outside is radiated through the metal door. The door radiates energy that is detected by the person's hand.
C
A student wants to increase the temperature of an ideal gas in a cylinder that is initially at room temperature. The cylinder has a movable piston with negligible friction. Which of the following correctly indicates an action the student could take to increase the temperature of the gas, and why the temperature increases? A Pull the piston out rapidly. The gas will expand violently and increase in temperature. B Pull the piston out slowly. The gas will have time to absorb energy from the surroundings by heating as it expands. C Push the piston in rapidly. The temperature of the gas will increase because no energy will be transferred to the surroundings by cooling. D Push the piston in slowly. The gas will have time to absorb energy from the surroundings by heating as it is compressed.
C
About 1 × 10^-29 kg of mass is lost when an atom of a certain isotope of plutonium, Pu-239, undergoes a single alpha decay. A small sample is composed of 3 × 10^19 Pu-239 atoms. If all the nuclei in the sample undergo alpha decay, the energy released is most nearly A 9 × 10^-13 J B 9 × 10^-2 J C 3 × 10^7 J D 3 × 10^21 J
C
An atom of polonium ( Po-216 ) is moving slowly enough that it can be considered to be at rest. The Po-216 undergoes alpha decay and becomes lead ( Pb-212 ), via the reaction 21684Po→21282Pb+42α84216��→82212��+24�. After the decay, the lead atom is moving to the left with speed vPb , and the alpha particle is moving to the right with speed va. The masses of the three isotopes involved in the decay are given below. M Po-216 = 216.001915 u M α = 4.002603 u M Pb-212 = 211.991898 u How much energy is released in the decay? A None B 0.00741 MeV C 6.90 MeV D 9.31 MeV
C
An atom of polonium ( Po-216 ) is moving slowly enough that it can be considered to be at rest. The Po-216 undergoes alpha decay and becomes lead ( Pb-212 ), via the reaction 21684Po→21282Pb+42α84216��→82212��+24�. After the decay, the lead atom is moving to the left with speed vPb , and the alpha particle is moving to the right with speed va. The masses of the three isotopes involved in the decay are given below. M Po-216 = 216.001915 u M α = 4.002603 u M Pb-212 = 211.991898 u The half-life of Po-216 is 1/7 s. What is the probability that any particular Po-216 atom will decay within one second? A 0 % B 7 % C 99 % D 100 %
C
Radioactive element X has a half-life of approximately 50 days. Radioactive element Y has a half-life of approximately 100 days. A 0.8 g sample of element X and a 0.8 g sample of element Y are weighed and examined. Some time later, both samples are measured again and 0.2 g of element X remains. How much of element Y remains? A 0.1 g B 0.2 g C 0.4 g D 0.8 g
C
The figures above show three circuits, each containing the same battery and identical capacitors. Which circuit has the largest stored charge when it reaches steady state? A X B Y C Z D All three store the same charge.
C
The graph above shows the electric field E of an electromagnetic wave as a function of position x at a particular instant. Which of the following equations, where all quantities are assumed to have units consistent with the graph, best represents the graph? A E=10 cos(2πx/10) B E=10cos(2πx/5) C E=5cos(2πx/10) D E=5cos(2πx/5)
C
A hollow prism in the shape of a right triangle is shown in the figure above. The prism is filled with a liquid and can be placed in any of the three orientations shown. The liquid-filled prism is placed in a large tank containing a different liquid and sinks to the bottom of the tank. FX is the magnitude of the buoyant force exerted on the prism by the liquid in the tank when the prism is in orientation X. FY and FZ are the buoyant forces for orientations Y and Z. Which of the following correctly ranks the three buoyant forces? A FY<FX<FZ B FZ<FX<FY C (FX=FY)<FZ D FX=FY=FZ
D
A rectangular loop of copper wire is attached to a cart by an insulating rod. The cart is moving at constant speed when it enters a region containing a uniform magnetic field that is perpendicular to the plane of the loop and directed into the page, as shown above. Frictional losses are negligible. Which of the following correctly describes the speed of the cart as it moves into, through, and out of the field? A The speed remains constant. B The speed continually decreases. C The speed decreases as the cart enters the field and increases as it leaves the field but is constant while it is completely inside the field. D The speed decreases as the cart enters and leaves the field but is constant while it is completely inside the field.
D
A sealed container with a lid of area 0.004 m^2 is filled with an ideal gas. The container and gas are allowed to reach thermal equilibrium with the surrounding air. If a 2000 N block is needed to keep the lid from being pushed off the container, what is the absolute pressure inside the container (the pressure compared to vacuum) ? A 1 x 10^5 Pa B 2 x 10^5 Pa C 4 x 10^5 Pa D 6 x 10^5 Pa
D
A simple ideal gas is enclosed in a cylinder with a movable piston. The gas is initially in state A at a temperature of 190 K and is taken from state A to state B along the path shown in the graph above of pressure P as a function of volume V. What is the temperature of the gas in state B ? A 38 K B 190 K C 380 K D 950 K
D
The energy level diagram for a hypothetical atom is shown in the figure above. Which of the labeled transitions in the diagram would produce a photon with the shortest wavelength? A A B B C C D D (longest arrow, leaps thru most eV)
D
Two wave pulses approach each other, as shown in the figure above. The pulse traveling to the right is half the height and twice the width of the pulse traveling to the left. Which of the following best represents the resulting shape when the peaks of the two pulses are at the same location? A two small curves under B one big curve above C flat line D two small curves under, one big one above in the middle
D
Directions: For the question or incomplete statement below, two of the suggested answers are correct. For this question, you must select both correct choices to earn credit. No partial credit will be earned if only one correct choice is selected. Select the two that are best in each case. On a calm day, student 1 looks down into a pool and sees student 2 swimming underwater. At the same time, student 2 looks up from under the water and sees student 1. In the following diagrams, the oval represents student 1 and the rectangle represents student 2. Diagrams that correctly illustrate the apparent positions seen by student 1 and student 2 include which of the following? Select two answers. A two rectangles under line, dotted rectangle is higher B two rectangles under line, solid rectangle is higher C two circles above line, dotted circle is higher D two circles above line, solid circle is higher
two rectangles under line, dotted rectangle is higher two circles above line, dotted circle is higher
A sample of gas is in a sealed container whose volume is held fixed. The pressure of the gas is measured as its absolute temperature is increased. A graph of pressure measurements as a function of temperature is shown above. According to the ideal gas law, which of the following is expected if the sealed container's volume is increased to three times the original value and the experiment is repeated? A The graph will show a linear relationship that still extrapolates to the origin, but with a smaller slope. B The graph will show a linear relationship that still extrapolates to the origin, but with a larger slope. C The graph will show a linear relationship with the same slope, but it will extrapolate to a point on the horizontal axis to the right of the origin. D The graph will show a linear relationship with the same slope, but it will extrapolate to a point on the vertical axis above the origin.
A
A sample of ideal gas that is initially in state A shown on the graph above is taken through the cycle shown. What is the net work done on the gas during one cycle? A -500 J B -1000 J C -2000 J D -3500 J
A
A student is doing experiments involving magnetic fields with the two long wires shown above, which are in the plane of the page. The student connects the ends of the left wire to a battery, creating a current in the wire toward the bottom of the page. What is the direction of the magnetic field at the location of the right wire? A Out of the page B Into the page C Toward the left D Toward the right
A
An ideal fluid with density 960 kg/m3 fills the pipe shown in the side view above and flows through it. The pipe has a circular cross section, and the speed of the fluid at point A is 0.6 m/s . The difference in the pressure of the fluid at points A and B is most nearly A 1.2 × 10^3 Pa B 2.6 × 10^3 Pa C 3.8 × 10^3 Pa D 6.4 × 10^3 Pa
A
Electronic transitions between the n = 2 and n = 4 energy levels of a hydrogen atom are associated with the emission or absorption of photons of visible light of frequency f. Which of the following statements about the electronic transition from the n = 1 to the n = 4 energy level of hydrogen must be true as a consequence of energy conservation? A A photon with a frequency greater than f must be absorbed by the atom. B A photon with a frequency greater than f must be emitted by the atom. C A photon with a frequency smaller than f must be absorbed by the atom. D A photon with a frequency smaller than f must be emitted by the atom.
A
Louis de Broglie proposed that all forms of matter have both wave properties and particle properties. Which of the following explains why diffraction effects are observable only for small-scale objects? A Wavelengths of large-scale objects are much smaller than any aperture through which the objects could pass. B Wavelengths of large-scale objects are much larger than any aperture through which the objects could pass. C Large-scale objects have too much energy to allow observation of their wave properties. D Large-scale objects move too slowly to allow observation of their wave properties.
A
Some students collect data to determine the focal length of a concave mirror. Using a small candle as the object, they move a piece of white cardboard until they see a focused image of the candle flame on it. The students measure the distances of the candle and the image from the mirror. A graph of the data is shown above. Which of the following is closest to the focal length of the mirror? A 10 cm B 15 cm C 20 cm D 30 cm
A
The circuit shown above includes a battery, two resistors, and a capacitor with values as labeled. The current through the battery is I. Which of the following is a correct equation for potential differences in the circuit a long time after the switch is closed? A ε − IR1 − IR2 = 0 B ε + IR1 + IR2 = 0 C ε − IR1 − IR2 − Cε = 0 D ε − IR1 − IR2 + Cε = 0
A
The figure above shows lines of equal electric potential in a region of space in the plane of the page. At which labeled point is the magnitude of the electric field greatest? A A B B C C D D
A
The graph above represents the magnitude E of the electric field at a point in space as a function of time t. Which of the following is a correct equation for the field if E is in V/m and t is in s ? A E = 3cos (2πt / 5) B E = 3cos (2πt / 3) C E = 5cos (2πt / 5) D E = 5cos (2πt / 3)
A
Three charged particles are near each other but isolated from other objects. Particle L has a charge of +2.0μC and is located 4.0 cm above the origin on the positive y-axis. Particle M has a charge of −4.0μC and is located 8.0 cm directly below particle L. Particles L and M are fixed in place. Particle N has a charge of −1.0μC and is released from rest at 3.0 cm from the origin on the positive x-axis. Which of the following shows the initial direction of motion of particle N ? A up, slight right B right, slight up C down, slight left D left, slight up
A
Two conducting plates of area A are separated by a distance d, as shown above. The upper plate has a net charge of +Q and the lower plate has a net charge of -Q . Point P is located a distance s above the center of the lower plate and closer to the lower plate than the upper plate. Assume the plate dimensions are very large compared to d and all gravitational forces are negligible. If the magnitude of the electric field at point P is 5.0 × 10^4 N/C and the distance between the plates is 0.80 mm , what is the electrical potential difference between the plates? A 40 V B 62.5 V C 4000 V D 6250 V
A
Two identical containers, X and Y, each contain one mole of an ideal monatomic gas. The atoms in container X have a higher average kinetic energy than those in container Y. The containers are thermally insulated from the external environment and placed into thermal contact with each other at time t=0. Which of the following accurately describes the interactions between containers X and Y ? A The net result is that energy is transferred from container X to container Y. B The amount of energy transferred between the containers depends on the type of atoms each contains. C After equilibrium is reached, the atoms in container X will still have a different average kinetic energy than those in container Y. D All the atoms in container X slow down, and all the atoms in container Y speed up.
A
Small solid sphere X is made of an insulating material and has negative charge distributed throughout its volume. Small solid sphere Y is made of a conducting material and is also negatively charged. The spheres are initially far apart and are then brought near each other, as shown above. Which of the following cross sections best represents the charge distribution on the two spheres when they are near each other? ; A X & Y both negative evenly distributed B X disorganized negative, Y evenly distributed negative C X disorganized negative, Y all negative to the right D X all negative to the left, Y all negative to the right
C
Two samples of the same type of gas molecules are placed in different closed containers and are thermally isolated from each other and the environment. The figure above shows the distribution of speeds for the molecules in each of the samples. The two samples are now mixed together and allowed to reach thermal equilibrium. Which of the following is true of the peak of the distribution for the mixed sample? A It is closer to 400 m/s than it is to 800 m/s B It is closer to 800 m/s than it is to 400 m/s . C It is midway between the peaks of the distributions shown. D There is not just one peak but two, at the same locations as the peaks of the distributions shown.
A
When light of frequency ƒP is incident on a metal with threshold frequency ƒ0, electrons are ejected with maximum kinetic energy KP . This is represented in the graph above by point P. How would the location of point P on the graph change if the intensity of the same light source were increased? A P would not move. B P would move vertically up. C P would move horizontally to the right. D P would move diagonally up and to the right
A
One way to model the allowed states of a hydrogen atom is to treat the atom's single electron as a standing wave with a wavelength l . Which of the following could be the radius of the orbit of the electron in such a model? Select two answers A 2 λ / π B λ / 4π C λ / 2π D λ / 2
A, C
Directions: For the question or incomplete statement below, two of the suggested answers are correct. For this question, you must select both correct choices to earn credit. No partial credit will be earned if only one correct choice is selected. Select the two that are best in each case. An ideal fluid is moving from left to right through a pipe, as shown in the figure above. The diameter of the pipe decreases and the height increases from left to right. True statements about the pressure of the fluid as it moves through the pipe include which of the following? Select two answers. A The pressure tends to decrease due to the increase in the fluid's speed as the pipe gets narrower. B The pressure tends to increase due to the decrease in the fluid's speed as the pipe gets narrower. C The pressure tends to decrease due to the increase in the potential energy of the fluid-Earth system as the pipe gets higher. D The pressure tends to increase due to the increase in the potential energy of the fluid-Earth system as the pipe gets higher.
A, C (decrease, decrease)
Directions: For the question or incomplete statement below, two of the suggested answers are correct. For this question, you must select both correct choices to earn credit. No partial credit will be earned if only one correct choice is selected. Select the two that are best in each case. A student is given two different convex spherical mirrors and asked to determine which of the mirrors has the shorter focal length. Answering which of the following questions would allow the student to make this determination? Select two answers. A Which mirror has a larger magnification for a given object distance? B Which mirror has the greater change in magnification when submerged in water? C Which mirror produces an upright image? D Which mirror has a smaller radius of curvature?
A, D
A circuit containing only a lightbulb is placed in a uniform magnetic field B⃗ �→ directed into the page, as shown above on the left. The variation of the magnetic field as a function of time is shown in the graph. During which of the following intervals will the bulb be brightest? A 0-2 s B 2-4 s C 4-6 s D 6-7 s
B
A closed chamber filled with a gas that is modeled as ideal has a movable piston of area A. The graph above of pressure P as a function of volume V shows three processes that make up cycle XYZX through which the gas is taken. Process ZX is isothermal. During which process is no work done on or by the gas? A XY B YZ C ZX D Work was done on or by the gas during every process
B
A cube of mass m with sides of length s is completely submerged in a tank of fluid of density r and held in place by a string attached to the bottom of the tank, as shown above. The height of the fluid is h, and the string has a nonzero tension FT. Which of the following is a correct expression for the density of the cube? A (ps^3g + FT) / s^3g B (ps^3g - FT) / s^3g C (FT + mg) / s^3g D (FT - mg) / s^3g
B
A battery with emf 6.0 V and an internal resistance r is connected to a resistor of resistance R, as shown in Figure 1 above. The current in the circuit is 2.0 A. When an identical battery is added to the circuit in series, as shown in Figure 2, the current in the circuit is 3.0 A. Which of the following statements about the resistances in the circuit is true? A r is very small compared to R. B r is very large compared to R. C r is equal to R. D r and R are comparable in magnitude, but they are not equal.
D
A fixed quantity of an ideal monatomic gas is enclosed in a container of fixed volume. Which of the following is true and helps explain why a decrease in the temperature of the gas results in a decrease in its pressure? A The speed of each of the molecules decreases, so the molecules all exert less force on the container when they collide with it. B The average speed of the collection of gas molecules decreases, so on average the molecules exert less force on the container when they collide with it. C The speed of only the fastest molecules decreases, so the molecules have fewer collisions with the container. D The speeds of the molecules are more evenly distributed across all possible values, so the molecules have fewer collisions with the container.
B
A hollow prism in the shape of a right triangle is shown in the figure above. The prism is filled with a liquid and can be placed in any of the three orientations shown. The prism is emptied of liquid. It is then submerged in another liquid with refractive indexes of 1.3 for red light and 1.4 for blue light. A beam of white light enters the prism. Which of the diagrams below shows the paths of red and blue light rays as they exit the prism? A blue, then red, then dotted, all pointing right B red, then blue, then dotted, all pointing right C red, then blue, both pointing left, then dotted, pointing right D blue, then red, both pointing left, then dotted, pointing right
B
A parallel-plate capacitor is charged so that an electric field E is created between the plates. A small oil drop with charge +q is placed halfway between the plates, as shown in Figure 1 above. The force exerted on the oil drop by the electric field is determined to have a magnitude of F. The oil drop is now moved half the distance toward the negatively charged plate, as shown in Figure 2 above. What is the magnitude of the force exerted by the electric field on the oil drop at the position shown in Figure 2 ? A F/2 B F C 2F D 4F
B
A piece of a thick ring of metal with height h and resistance R is connected to a battery, creating a uniform current I throughout the piece of ring, as shown in the figure above. A second piece of a ring has height 2h but is otherwise identical to the first piece. The second piece of ring is connected to the battery in the same way as the first piece. What is the resistance of the second piece? A R/4 B R/2 C 2R D 4R
B
A sample of a gas is in a container with a movable piston. Only one action is performed to take the gas from state A to state B via the process shown in the above graph of pressure as a function of volume. Which of the following could be the one action? A Gas molecules were removed from the container. B Thermal energy was added to the gas. C The piston was pulled out. D The gas was allowed to freely expand.
B
A student has three sunglass lenses. Lenses A and B have identical polarization patterns, and lens C is not polarized. Which of the following arrangements of lenses would have the most light blocked where the lenses overlap? A lens B over A, both horizontal B lens B over A, lens B vertical, lens A horizontal C lens C over A, both horizontal D lens C over A, lens B vertical, lens A horizontal
B
A supernova explosion occurs at a distance of 2×10^20 m from Earth. The supernova simultaneously emits radiation at both visible and x-ray wavelengths. Which of the following statements best describes the time it takes for the two types of radiation from the supernova to reach Earth? A The two types of radiation reach Earth at the same time, within a few seconds of the supernova explosion. B The two types of radiation reach Earth at the same time, many years after the supernova explosion. C The two types of radiation reach Earth many years after the supernova explosion, but the visible radiation arrives first due to its shorter wavelength. D The two types of radiation reach Earth many years after the supernova explosion, but the x-ray radiation arrives first due to its shorter wavelength.
B
A very small, isolated sphere with charge +Q exists in an empty region of space. A second very small sphere is moved from far away to a short distance from the first sphere The second sphere has a charge of +2.0 x 10^-9 C. As it is moved closer to the first sphere at a constant speed, the second sphere passes through the circular equipotential lines due to the first sphere. Two of these lines are separated by a distance of 0.020 m and have potentials of 100 V and 150 V. What is the magnitude of the average force needed to move the second sphere between the two equipotential lines? A 1.5 x 10^-5 N B 5.0 x 10^-6 N C 1.0 x 10^-7 N D 2.0 x 10^-9 N
B
Some students drew the figure above as a representation that could be either a topographic (elevation) map, with the arrows representing the direction of downward slope, or electric equipotentials and electric field direction near some charged particles. Which of the following correctly describes what is inside the empty regions for each representation? A Topographic Map: Peak at upper left; valley at lower right Electric Potentials and Field: Negative charge at upper left; positive charge at lower right B Topographic Map: Peak at upper left; valley at lower right Electric Potentials and Field: Positive charge at upper left; negative charge at lower right C Topographic Map: Valley at upper left; peak at lower right Electric Potentials and Field: Negative charge at upper left; positive charge at lower right D Topographic Map: Valley at upper left; peak at lower right Electric Potentials and Field: Positive charge at upper left; negative charge at lower right
B
The graphs above show the electric field as a function of position at some instant of time for four different electromagnetic plane waves. Which of the following correctly ranks the frequency f of the waves? A f1 > f2 > f3 > f4 B f1 > f3 > f4 > f2 C f2 > f4 > f3 > f1 D f4 > f3 > f2 > f1
B
What are the value and the direction of the current through the 5 Ω resistor in the circuit shown above? A 1.0 A toward the top of the page B 1.0 A toward the bottom of the page C 2.0 A toward the top of the page D 2.0 A toward the bottom of the page
B
A block floating in water is supported by the buoyant force exerted on the block by the water. The buoyant force is created on the atomic scale primarily by which of the following electrostatic forces? A A force of attraction between neutral atoms of the block and neutral atoms of the water B A force of attraction between charged atoms of the block and charged atoms of the water C A force of repulsion between nuclei in the neutral atoms of the block and nuclei in the neutral atoms of the water D A force of repulsion between electrons in the neutral atoms of the block and electrons in the neutral atoms of the water
D
Which of the following is a correct description of the field diagram shown above? A It shows field vectors for two particles with charges of opposite sign and about the same magnitude, and it could also represent their gravitational field if they have about the same mass. B It shows field vectors for two particles with charges of opposite sign and about the same magnitude, but it could not represent their gravitational field. C It shows field vectors for two particles with charges of the same sign and about the same magnitude, and it could also represent their gravitational field if they have about the same mass. D It shows field vectors for two particles with charges of the same sign and about the same magnitude, but it could not represent their gravitational field.
B
Which of the following accurately describe how the kinetic energy of atoms in a sample of monatomic ideal gas changes when the temperature is increased? Select two answers. A The kinetic energy of each individual atom in the gas increases. B The kinetic energy of each individual atom in the gas may increase or decrease. C The average kinetic energy of the whole sample of atoms increases. D The kinetic energy of some individual atoms increases, but the average kinetic energy of the whole sample of atoms does not change.
B, C
A beam of identical positively charged ions moves from left to right between two parallel plates, as shown in the figure on the left above. A wire is located below the plates and parallel to the ion beam. The distance between the plates, the length of the plates, and the distance between the ion beam and the wire are known. A current I in the wire deflects the ion beam from a straight path. The potential difference e across the plates is then adjusted to return the beam to the straight path. The graph above plots the potential difference across the plates as a function of the current in the wire. Which of the following can be determined from the slope of the graph? Select two answers. A The mass of an ion in the beam if the charge on the ion is known B The average speed of the ions in the beam C The amount of charge on an ion in the beam if the mass of the ion is known D The time an ion spends between the plates
B, D
A monatomic ideal gas in a sealed container is taken from state W to state Z through intermediate states X and Y, as shown in the above graph of pressure P as a function of volume V. The internal energy of the gas in state X is the same as that in which other state? A W B Y C Z D None of the other states
C
A monatomic ideal gas in a sealed container is taken from state W to state Z through intermediate states X and Y, as shown in the above graph of pressure P as a function of volume V. What is the total work done on the gas as it goes from state W to state Z ? A 0 B −P0V0 C −2P0V0 D −4P0V0
C
A proton moving to the right in the plane of the page with speed v enters a magnetic field of magnitude B directed toward the top of the page. What is the direction of the initial magnetic force that is exerted on the proton? A Toward the top of the page B Into the page C Out of the page D No direction, because there is no magnetic force on the proton
C
A student designs an experiment intended to determine the thermal conductivity of an unknown material. Two 15 cm long bars with the same cross-sectional area are joined together, as shown in the figure above. The bar on the left is made of copper, and the bar on the right is made of the unknown material. The left and right ends of the two-bar combination are maintained at 40°C and 20°C , respectively, and the bars reach equilibrium. The student then measures the temperature T along the bars and produces the data shown in the graph, where x = 0 is the left end and 30 cm is the right end. The experimental uncertainty in the data is negligible. Which of the following can the student conclude about kc, the thermal conductivity of copper, compared with ku , the thermal conductivity of the unknown material? A kc < ku B kc = ku C kc > ku D The relationship cannot be determined from the data given.
C
A student performs an experiment using the circuit shown above, with the goal of determining the characteristics of the battery, which has nonnegligible internal resistance. The student has many resistors with resistances ranging from 0.5 Ω to 15 Ω. The student puts different resistors in the circuit and records the current and the potential difference measured by the ammeter A and voltmeter V. The student's data table and graph of current as a function of potential difference are shown below. Which of the following is most nearly the battery's internal resistance? A 0.4 ohm B 0.6 ohm C 1.6 ohm D 2.6 ohm
C
A student uses a convex lens to create images and collects the data shown above. The focal length of the lens is in which of the following ranges? A 0-5 cm B 5-10 cm C 10-15 cm D 15-25 cm
C
A very small, isolated sphere with charge +Q exists in an empty region of space. A second very small sphere is moved from far away to a short distance from the first sphere In the figures below, the central dot represents the first sphere. The dashed circles are isolines with the same potential difference between adjacent circles. Which of the figures best represents the isolines and electric field vectors around the first sphere while the second sphere is still far away? A arrows close inwards B arrows slightly further away, inwards C arrows outwards, the inner circles are similar sizes both kind of far from middle D arrows outwards, one of the inner circles is close to the middle
C
An atom of polonium ( Po-216 ) is moving slowly enough that it can be considered to be at rest. The Po-216 undergoes alpha decay and becomes lead ( Pb-212 ), via the reaction 21684Po→21282Pb+42α84216��→82212��+24�. After the decay, the lead atom is moving to the left with speed vPb , and the alpha particle is moving to the right with speed va. The masses of the three isotopes involved in the decay are given below. M Po-216 = 216.001915 u M α = 4.002603 u M Pb-212 = 211.991898 u How do the momentum and kinetic energy of the polonium atom compare with the total momentum and kinetic energy of the decay products? Polonium Momentum | Polonium Kinetic Energy A Different | Different B Different | The same C The same | Different D The same | The same
C
An electron is moving to the right, as shown in the figure above. It passes through the shaded region, which contains a magnetic field directed into the page. The electron travels along a path that takes it through point P. The gravitational force on the electron is negligible. Which of the following is a possible path of the electron? A linear line B linear line thru the grey, still straight after but more down C curvey through, gets a bit more straight before the end D curvey all the way
C
In the circuit represented above, resistors R1 and R2, capacitor C, and open switch S are connected to a battery. The circuit reaches equilibrium. The switch is then closed, and the circuit is allowed to come to a new equilibrium. Which of the following is a true statement about the charge qf stored on the capacitor after the switch is closed compared with the charge qi stored on the capacitor before the switch is closed? A qf > qi B qf = qi C qf < qi D The relationship between the charges cannot be determined unless the resistances of the resistors are known.
C
Some students are trying to determine whether the radius of a metal sphere affects the amount of charge that it can hold. The students have metal spheres of different radii and known masses that can be attached to a stand by a string, as shown above. The stand is midway between a set of large plates that are connected to a battery to create a nearly uniform electric field in the region between them and near their centers. The students rub a rod with cloth and touch it to each sphere to charge the sphere, and they observe the deflection of the sphere as it is attracted to one plate. They keep adding charge to each sphere until they cannot observe any change in deflection. Which of the following data will give them information that is useful for quantitatively comparing the amount of charge on each sphere? A The number of times they rub the cloth back and forth on the rod B The number of times they touch the rod to the sphere C The string's angle of deflection D The string's direction of deflection
C
The graph above of pressure as a function of volume illustrates a thermodynamic process for an ideal gas in an engine. Which of the following best describes the change in the internal energy of the gas and the work done during the process? A The internal energy increases, and positive work is done by the gas. B The internal energy decreases, and positive work is done on the gas. C The internal energy decreases, and positive work is done by the gas. D The internal energy increases, and positive work is done on the gas.
C
Two conducting plates of area A are separated by a distance d, as shown above. The upper plate has a net charge of +Q and the lower plate has a net charge of -Q . Point P is located a distance s above the center of the lower plate and closer to the lower plate than the upper plate. Assume the plate dimensions are very large compared to d and all gravitational forces are negligible. Which of the following indicates the direction of the electric field at point P and the reason it has that direction? A The electric field is in the +x direction because the charges are equal and opposite. B The electric field is in the -y direction because point P is farther from the positively charged plate. C The electric field is in the -y direction because electric fields point away from positive charge and toward negative charge. D The electric field is in the +y direction because electric fields point away from negative charge and toward positive charge.
C
Two uncharged conducting spheres on insulating stands are in contact when a positively charged rod is brought near but does not touch them, as shown in the figure above. The right sphere is then moved far to the right, and finally the rod is removed. Which of the following best shows the final distribution of excess charges, if any, on the spheres? A both empty B left negative right empty C left negative right positive D left positive right negative
C
When two bowling balls are held with their centers 30 centimeters apart, they exert a gravitational force of magnitude F on each other. For two free protons to exert a net force of magnitude F on each other, the protons must be separated by a distance of approximately 1 × 10^-10m. Under these conditions, will the protons attract or repel each other, and why? A They will attract each other, because they both have positive charge. B They will attract each other, because the gravitational force is always attractive. C They will repel each other, because the repulsive electrical force between the protons is much stronger than the attractive gravitational force. D They will repel each other, because the protons only exert a repulsive electrical force on each other and do not exert an attractive gravitational force.
C
A cube of mass m with sides of length s is completely submerged in a tank of fluid of density r and held in place by a string attached to the bottom of the tank, as shown above. The height of the fluid is h, and the string has a nonzero tension FT. Which of the following indicates how the density of the cube compares with the density of the fluid and provides correct evidence for the comparison? A The fact that the cube is completely submerged is evidence that the density of the cube is greater than the density of the fluid. B The fact that the cube is completely submerged is evidence that the density of the cube is less than the density of the fluid. C The fact that there is tension in the string is evidence that the density of the cube is greater than the density of the fluid. D The fact that there is tension in the string is evidence that the density of the cube is less than the density of the fluid.
D
A monatomic ideal gas in a sealed container is taken from state W to state Z through intermediate states X and Y, as shown in the above graph of pressure P as a function of volume V. The gas is now taken from state Z to state M via an isovolumetric process in which its temperature increases. Which of the following graphs could represent this process? A left B right C down D up
D
A simple circuit has a 24.0 V battery and resistors of resistance 3.0 Ω, 6.0 Ω, and R all connected in parallel. If the current through the battery is 15.0 A, what is the value of R ? A 0.9 Ω B 1.1 Ω C 7.4 Ω D 8.0 Ω
D
A student is doing an experiment in which monochromatic light passes through a double slit, creating a pattern of dark and bright lines on a nearby screen. The student has a red light and a green light. The student also has two sets of slits, one with a small separation between the slits and one with a large separation. Which of the following lists the color and slit separation that will create the pattern with the greatest separation between the bright lines? A Color Slit Separation Green Large B Color Slit Separation Green Small C Color Slit Separation Red Large D Color Slit Separation Red Small
D
A student performs an experiment using the circuit shown above, with the goal of determining the characteristics of the battery, which has nonnegligible internal resistance. The student has many resistors with resistances ranging from 0.5 Ω to 15 Ω. The student puts different resistors in the circuit and records the current and the potential difference measured by the ammeter A and voltmeter V. The student's data table and graph of current as a function of potential difference are shown below. The student now replaces the battery with a different one that has the same emf but a significantly smaller internal resistance. The student runs the experiment again and graphs the new data. Which of the following correctly describes how the new graph compares to the plot shown above? A The new graph will be the same as the original graph. B The vertical intercept will have a greater value, but the slope will be the same. C The vertical intercept will be the same, but the magnitude of the slope will be greater. D Both the vertical intercept and the magnitude of the slope will be greater.
D
A student wishes to determine if a particular lightbulb is an ohmic resistor. The student assumes that the intensity of light from the bulb is directly proportional to the power it dissipates. The student measures the light intensity at one location near the bulb and the current through the bulb as the voltage across the bulb is varied. The data are shown above. Based on the data, is the bulb ohmic, and why? A No, because the power is a linear function of the current. B No, because the power is a quadratic function of the current. C Yes, because the power is a linear function of the current. D Yes, because the power is a quadratic function of the current.
D
A toy boat sits atop a cylinder of ice in a beaker, as shown above on the left. A normal force is exerted on the boat by the surface of the ice. Later the ice has melted, and the boat floats while partially submerged in the water, as shown on the right. A buoyant force is exerted on the boat by the water. Which of the forces, if either, is greater and why? A The normal force is greater because molecules in solids exert larger interatomic forces on other objects than molecules in liquids do. B The buoyant force is greater because more molecules of water are in contact with the boat, so the net interatomic force between the water and the boat is greater. C The forces are equal because each molecule of ice in contact with the boat exerts the same interatomic force on the boat as each molecule of water in contact with the boat. D The forces are equal because in both cases the net interatomic force exerted by the ice or water on the boat and the gravitational force on the boat balance.
D
A very small, isolated sphere with charge +Q exists in an empty region of space. A second very small sphere is moved from far away to a short distance from the first sphere As the second sphere is moved at a constant velocity closer to the first sphere, data is taken for the force F exerted on the second sphere by the first sphere as a function of the separation d of the spheres. Which of the following should be graphed to yield a straight line from the data? A F as a function of d B F as a function of d^2 C F as a function of 1/d D F as a function of 1/d^2
D
Four horizontal wires are arranged on vertical wooden poles, as shown in the figure above. The wires are equally spaced and have equal currents I in the directions indicated in the figure. The dots represent four charged dust particles moving in the plane of the wires. The sign of the charge on each particle and its direction of motion at a particular instant are shown. Which of the dust particles has a magnetic force exerted on it in the downward direction at this instant? A A B B C C D D
D
Student 1 brings a negatively charged rod with an insulating handle near to but not touching an uncharged metal sphere and finds that the objects attract. She wants the sphere to be repelled by the rod. Student 2, who is uncharged, suggests that this can be accomplished if he touches the sphere. Which of the following indicates whether this will work, and if so, gives a procedure that will cause the repulsion? A Yes, Student 2 could touch the sphere while the rod is held near it, because that would make the sphere negatively charged. B Yes, Student 2 could touch the sphere while the rod is kept far away, because that would make the sphere negatively charged. C Yes, Student 2 could touch the sphere while the rod is kept far away, because that would make the sphere positively charged. D No, there is no way that having Student 2 touch the sphere will work.
D
The circuit shown above contains four identical resistors connected to a battery and a switch. Which of the following correctly describes the direction of the current, if any, between points A and B when the switch is open and when it is closed? A Switch Open Switch Closed From B to A From B to A B Switch Open Switch Closed From B to A From A to B C Switch Open Switch Closed From A to B No current D Switch Open Switch Closed From A to B From B to A
D
The figure above represents three identical closed containers holding the same number of moles of different gases at the same temperature. From left to right, the gases are in order from smallest molar mass (H2) to largest molar mass (O2 ) . Modeling the gases as ideal, which gas, if any, has the greatest internal energy? A H2 B N2 C O2 D All have the same internal energy.
D
The figure above shows a lens with a focal length of magnitude 30 cm when in air. An object is located 200 cm to the left of the lens. What is the approximate location of the object's image? A 26 cm to the left of the lens B 26 cm to the right of the lens C 35 cm to the left of the lens D 35 cm to the right of the lens
D
The graph above describes the location of an electron in a hydrogen atom that is in the ground state. What conclusion can be drawn from the graph? A The distance of the electron from the nucleus is exactly equal to one Bohr radius. B The electron will probably slide down either the left slope or the right slope, depending on its initial location. C The electron must always be located within three Bohr radii of the nucleus. D The greatest probability of locating the electron is at a distance of one Bohr radius from the nucleus.
D
The three reactions shown above, with unidentified particles X and Y, occur in the manufacturing process of plutonium. What particles do X and Y represent? X ; Y A X neutron, Y alpha B X Y, Y B- C X Y, Y alpha D X neutron, Y B-
D
Two conducting plates of area A are separated by a distance d, as shown above. The upper plate has a net charge of +Q and the lower plate has a net charge of -Q . Point P is located a distance s above the center of the lower plate and closer to the lower plate than the upper plate. Assume the plate dimensions are very large compared to d and all gravitational forces are negligible. Assume the magnitude of the electric field at point P is 5.0 × 10^4 N/C. What is the magnitude and direction of the force on an electron at point P due to the electric field? A 3.1 × 10^23 N in the same direction as the electric field B 3.1 × 10^23 N in the direction opposite to the electric field C 8.0 × 10^-15 N in the same direction as the electric field D 8.0 × 10^-15 N in the direction opposite to the electric field
D
Two waves are created in air and move toward outer space. Wave X cannot travel in the vacuum of outer space, but wave Y can. What types of waves are X and Y ? A Wave X Wave Y Electromagnetic Mechanical B Wave X Wave Y Electromagnetic Electromagnetic C Wave X Wave Y Mechanical Mechanical D Wave X Wave Y Mechanical Electromagnetic
D
Water initially moving through a small horizontal cylindrical pipe enters a new section of pipe with twice the radius of the initial pipe. What is the ratio of the speed of the water in the new section of pipe to the initial speed of the water? A 2/1 B 1/1 C 1/2 D 1/4
D
Which of the following describes a difference in the behavior of an electrically conducting sphere and that of an insulating sphere? A A conducting sphere can be charged by friction, but an insulating sphere cannot. B An uncharged object can be charged by touching it to a charged conducting sphere, but not by touching it to a charged insulating sphere. C When a conducting sphere is brought near a positively charged object, some of the sphere's electrons move closer to that object. No polarization occurs in the atoms of an insulating sphere. D Excess charge placed on a conducting sphere becomes distributed over the entire surface of the sphere. Excess charge placed on an insulating sphere can remain where it is placed.
D