1) The charge of an electron is. A) negative. B) positive. C) Electrons have no charge.

Transcription

1 1) The charge of an electron is A) negative. B) positive. C) Electrons have no charge. 2) Two like charges A) have no effect on each other. B) repel each other. C) must be neutrons. D) neutralize each other. E) attract each other. 3) Electrical forces between charges are normally strongest when the charges are A) close together. B) far apart. C) The electrical force is constant everywhere. 4) Coulomb's law says that the force between any two charges depends A) inversely on the square of the distance between the charges. B) directly on the size of the charges. C) both A and B D) none of the above 5) Electrical forces between charges depend on A) the quantity of charge involved. B) how far apart the charges are. C) both A and B. D) none of the above 6) When the distance between two charges is halved, the electrical force between the charges A) halves. B) quadruples. C) reduces to one fourth. D) doubles. 7) If you comb your hair and the comb becomes positively charged, your hair becomes A) negatively charged. B) uncharged. C) positively charged. 8) A difference between electrical forces and gravitational forces is that electrical forces include A) repulsive interactions. C) infinite range. E) none of the options listed B) the inverse square law. D) separation distance.

2 9) In a good insulator, electrons are usually A) semi-free to move around. B) free to move around. C) tightly bound in place. D) free to move around after an impurity has been added. E) not moving at all. 10) Objects can be charged by A)friction. B) induction. C) touching. D) all of the above 11) Charge carriers in a metal are electrons rather than protons, because electrons are A) relatively far from a nucleus. B) lighter. C) loosely bound. D) all of the above 12) To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with A) wood. B) steel. C) Either building will be just as safe or unsafe. 13) A conductor differs from an insulator in that a conductor has A) more electrons than an insulator. B) more electrons than protons. C) more protons than electrons. D) faster-moving molecules. 14) A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side of the can momentarily with your finger. The can is then A) negatively charged. B) positively charged. C) uncharged. D) charged the same as it was. 15) An electroscope is charged positively, as shown by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves A) spread farther apart. C) do not move. B) move closer together.

3 16) Lightning bolts occur between A) clouds and the ground. B) clouds. C) both. 17) To charge an object by induction, the process of grounding A) may or may not occur. B) always occurs. 18) When a charged cloud passes overhead, the ground below is charged by A)electrification. B) induction. C) deduction. D) polarization. 19) Bring a charged object near a conductor and then momentarily touch the conductor. This demonstrates charge by A)electrification. B) polarization. C) induction. D) deduction. 20) A rubbed balloon will stick to a wooden wall, which demonstrates charge A)potential. B) polarization. C) transfer. D) conservation. 21) Two charged particles held close to each other are released. As they move, the force on each particle increases. Therefore, the particles have A) the same sign. B) opposite signs. C) Not enough information given 22) The SI unit of charge is the A)joule. B) ampere. C) coulomb. D) newton. E) ohm. 23) The electrostatic force between two charges located 2 meters apart is 0.10 N. What will the force be between these charges when they are located 1 meter apart? A) N B) 0.05 N C) 0.10 N D) 0.20 N E) 0.40 N

4 24) A 2-C charge and a 4-C charge attract each other with 10 N of force. How much will a 2-C charge and an 8-N charge attract each other when placed the same distance apart? A) 40 N B) 8 N C) 20 N D) 5 N E) 10 N 25) Two charges separated a distance of 1 meter exert a 1-N force on each other. If the charges are pushed to a separation of 1/4 meter, the force on each charge will be A) 16 N. B) 8 N. C) 1 N. D) 2 N. E) 4 N. 26) In solid conductors, electric current is the flow of A)electrons. B) positive and negative charges. C) negative ions. D) protons. 27) An ampere is a A)voltage. B) type of charge. C) current. D) unit of resistance. E) unit of current. 28) An example of a voltage source is A) a dry cell. B) a car battery. C) rubbing a rubber rod with fur. D) a generator. E) all of the above 29) Electrical resistance in a wire depends on the wire's A)conductivity. B) thickness. C) length. D) all of the above 30) Compared to thin wires, electrical resistance in thick wires is A) greater. B) less. C) the same. 31) For most conductors, as their temperature increases, their resistance A) stays the same. B) decreases. C) increases.

5 32) Electrical resistance is measured in A) joules. B) amperes. C) watts. D) volts. 33) The primary reason a bird can perch harmlessly on bare high voltage wires is that A) a bird has a very large electrical resistance. B) a bird's feet are close together. C) there is no potential difference across the bird's feet. D) all of the above 34) Current from a battery is always A) AC. B) DC. 35) The resistance of your dry skin is usually around A) 100 ohms. B) ohms. C) 1 ohm. D) ohm. E) millions of ohms. 36) Electric power is defined as A) current times resistance. B) current divided by voltage. C) resistance times voltage. D) current times voltage. E) voltage divided by current. 37) Power outlets in our homes typically have a potential difference of A) 240 V. B) 120 A. C) 120 V. D) 60 A. E) 30 V. 38) What is the resistance of a toaster that uses 2 A of current when connected to a 120- volt power source? A) 120 ohms B) 240 ohms C) 60 ohms D) 2 ohms

6 39) If you accidentally grabbed the prongs of a partially plugged-in 120-V electrical plug on a day when your skin resistance was ohms, how much current would pass through your body? A) 120 A B) A C) A D) A E) 1000 A 40) When plugged into a 120-V wall outlet, how much current is used by a toaster rated at 1200 W? A) 1200 A B) A C) 10 A D) 120 A 41) A heater uses 20 A when connected to a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is A)$5.50. B) $0.22. C) $0.55. D) $ ) In order to form an electric circuit, you need to have A) a complete path for the current. B) wires or conductors to connect everything. C) a light bulb or some resistance. D) a power source. E) all of the above 43) In order for current to exist in a circuit, you must have A) two light bulbs in parallel. B) a complete path for the current. C) two light bulbs in series. D) a switch that is open. E) all of the above 44) A closed circuit is a circuit in which charge A) is prevented from flowing. B) can flow. 45) When two light bulbs are connected in series, the A) current through each light bulb is proportional to the resistance of the bulb. B) same amount of current always flows through each bulb. C) neither A nor B

7 46) The symbol used to represent resistance in a schematic diagram is A) two straight lines. B) a zigzag line. C) a single line that is broken and has a bend in it. D) one straight line. 47) When resistors are put in series next to each other, their overall resistance is A) the same as the resistance of one of the resistors. B) smaller than the resistance of any of the resistors. C) larger than that of any individual resistor. 48) When resistors are put in parallel with each other their overall resistance is A) larger than that of any other resistor. B) the same as the resistance of one of the resistors. C) smaller than the resistance of any of the resistors. 49) Fuses and circuit breakers are used to A) keep wires from getting overheated. B) break the circuit when too much current is being used. C) prevent overloading. D) protect us. E) all of the above 50) A short circuit occurs when A) the positive wire is connected directly to the negative wire. B) very short wires are used in the circuit. C) current lasts in the circuit for only a short time. D) all of the above 51) Two lamps, one with a thick filament and one with a thin filament, are connected in series. The current is greater in the lamp with the A) thick filament. B) thin filament. C) Current is the same in each lamp. 52) The total resistance of a 3-ohm resistor and a 6-ohm resistor in series is A) 2 ohms. B) 9 ohms. C) 18 ohms. D) 6 ohms. E) 3 ohms.

8 53) The total resistance of a 3-ohm resistor and a 6-ohm resistor in parallel is A) 2 ohms. B) 18 ohms. C) 3 ohms. D) 9 ohms. E) 6 ohms. 54) The current through two identical light bulbs connected in series is 0.25 A. The total voltage across both bulbs is 110 V. The resistance of a single light bulb is A) 44 ohms. B) 440 ohms. C) 220 ohms. D) 22 ohms. 55) The source of all magnetism is A) ferromagnetic materials. B) moving electric charges. C) tiny pieces of iron. D) tiny domains of aligned atoms. 56) Moving electric charges will interact with A) an electric field. B) a magnetic field. C) both A and B D) none of the above 57) An iron rod becomes magnetic when A) positive charges line up on one side and negative charges on the other side. B) the net spins of its electrons point in the same direction. C) its electrons stop moving and point in the same direction. D) positive ions gather at one end and negative ions at the other end. 58) Surrounding every moving electron is A) a magnetic field. B) an electric field. C) both A and B D) none of the above 59) Magnetism is due to the motion of electrons as they A) move around the nucleus. B) spin on their axes. C) both A and B D) none of the above

9 60) If the north pole of one magnet is brought near the south pole of another magnet, the poles will A) repel each other. B) attract each other. C) not interact with each other at all. 61) If you break a bar magnet in half, each half A) becomes a bar magnet with two poles. B) becomes unmagnetized. C) contains one magnetic pole. 62) If you put a small compass in a magnetic field, the compass will A) line up in a direction parallel to the magnetic field lines. B) swing randomly. C) seek electrical charge concentrations. D) line up in a direction perpendicular to the magnetic field lines. 63) Magnetic field strength is A) constant everywhere around a magnet. B) strongest close to a magnet. C) strongest far from a magnet. 64) Magnetic fields are produced by A) charges at rest. B) moving charged particles. C) moving particles. D) moving particles of earth. 65) Magnetic domains are A) regions that may or may not be magnetized. B) regions of atoms magnetically aligned. C) clusters of atoms randomly aligned. D) blocks of material. 66) Permanent magnets can be made by A) placing a piece of iron near a strong electromagnet. B) stroking material containing iron with a magnet. C) placing a piece of iron in a strong magnetic field. D) all of the above 67) The earth's magnetic field is most likely due to A) a magnetized solid inner core of the earth. B) convection currents in the molten part of the earth's interior. C) millions of small magnets buried in the earth. D) the rotation of the earth acting on all of the earth's electrons.

10 68) The earth's magnetic field reverses its polarity about once every A) 100,000 years. B) million years. C) 100 years. D) The earth's magnetic field never reverses its polarity. 69) Which geographic pole of the earth is nearest the magnetic north pole of the earth? A) North pole B) South pole C) both A and B 70) Which pole of a compass needle points to a south pole of a magnet? A) South pole B) North pole C) both A and B 71) If a compass is moved from the Northern Hemisphere to the Southern Hemisphere, its magnetic needle will change direction A) not at all. B) by 90 degrees. C) by 180 degrees. D) none of the above 72) Magnetic field lines surrounding a magnet are conventionally drawn A) from north to south. B) from south to north. C) either way. 73) Changing the magnetic field intensity in a closed loop of wires induces A) current. B) voltage. C) both. D) neither. 74) The magnetic field strength inside a current-carrying coil will be greater if the coil encloses a A) iron rod. B) vacuum. C) glass rod. D) wooden rod. 75) Most commercial generators are driven by A) wind. B) steam. C) rain.

11 76) Acceleration is defined as the CHANGE in A) time it takes to move from one place to another place. B) velocity divided by the time interval. C) distance divided by the time interval. D) velocity of an object. E) time it takes to move from one speed to another speed. 77) One possible unit of speed is A) miles per hour. B) kilometers per hour. C) light years per century. D) all of the above.. 78) Suppose an object is in free fall. Each second the object falls A) the same distance as in the second before. B) with the same instantaneous speed. C) a larger distance than in the second before. D) with the same average speed. 79) When something falls to the ground, it accelerates. This acceleration is called the acceleration due to gravity and is symbolized by the letter g. What is the value of g on the earth's surface? A) about 20 m/s 2 B) about 10 m/s 2 C) about 5 m/s 2 D)about 50 m/s 2 E) 0m/s 2 80) If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting point is about A) 20 seconds. B) 10 seconds. C) not enough information to estimate D) 2 seconds. E) 1 second. 81) If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by A) a variable amount. B) about 10 m/s. C) about 15 m/s. D) a rate that depends on its initial speed. E) about 5 m/s. 82) If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first? A) The coin B) The feather C) Neither-they will both reach the bottom at the same time.

12 83) As an object falls freely in a vacuum, its A) acceleration increases. B) velocity increases. C) both A and B D) none of the above 84) Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of A) 3 m. B) 5 m. C) 1 m. D) 2 m. E) 4 m. 85) The hang time (time one's feet are off the ground in a jump) for most athletes is A) about 1 second. B) considerably more than 1 second. C) slightly more than 1 second. D) less than 1 second. 86) Suppose you take a trip that covers 240 km and takes 4 hours to make. Your average speed is A) 240 km/h. B) 60 km/h. C) 960 km/h. D) 480 km/h. E) 120 km/h. 87) Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's average acceleration? A) 0.25m/s 2 B) 4.0m/s 2 C) 40m/s 2 D)10m/s 2 E) 2.5m/s 2 88) A car accelerates at 2m/s 2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30 m/s? A) 2 seconds B) 30 seconds C) 15 seconds D) 60 seconds 89) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always A) in the direction of motion. B) directed upward. C) directed downward. D) opposite its velocity.

13 90) Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. Which of the following is NOT true? A) Your direction is constantly changing. B) Your acceleration is constant. C) Your speed is constant. D) You and the car are accelerating. E) Your velocity is constant. 91) A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be A) less than the speed it had when thrown upwards. B) the same as the speed it had when thrown upwards. C) more than the speed it had when thrown upwards. 92) When you look at the speedometer in a moving car, you can see the car's A) instantaneous speed. B) average speed. C) instantaneous acceleration. D) average acceleration. E) average distance traveled. 93) One-half second after starting from rest, a freely falling object will have a speed of about A)5 m/s. B) 10 m/s. C) 20 m/s. D) 2.5 m/s. 94) Speed is A) always measured in terms of a unit of distance divided by a unit of time. B) the distance covered per unit time. C) a measure of how fast something is moving. D) all of the above.. 95) In the absence of air resistance, objects fall at constant A)speed. B) velocity. C) acceleration. D) distances each successive second. E) all of the above 96) A ball is thrown straight up. At the top of its path its instantaneous speed is A) about 5 m/s. C) 0 m/s. E) about 50 m/s. B) about 20 m/s. D) about 10 m/s.

14 97) An object travels 8 meters in the first second of travel, 8 meters again during the second second of travel, and 8 meters again during the third second. Its acceleration is A)0m/s 2. B) 8m/s 2. C) 16m/s 2. D)32m/s 2. 98) When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration A) depends on launch speed. B) is usually greater for taller players (but not always). C) varies with body orientation. D) depends on all the above. E) is g; no more, no less. 99) Ten seconds after starting from rest, a freely falling object will have a speed of about A) 100 m/s. B) 50 m/s. C) 10 m/s. D) 500 m/s E) more than 500 m/s. 100) Consider drops of water leaking from a water faucet. As the drops fall they A) get closer together. B) get farther apart. C) remain at a relatively fixed distance from each other.