Physics Final Review

A student uses a thermometer calibrated in Kelvin units. A temperature change of 20 K is equivalent to a change of how many degrees on the Celsius scale? ____________.

20

A charged comb attracts bits of neutral dust in the air. This happens because A) the dust becomes polarized. B) the dust grounds the comb. C) the dust becomes charged by induction. D) the dust is a good conductor.

A) the dust becomes polarized.

A 9 ohm resistor and a 16 ohm resistor are connected in series in a circuit with a 5.0 volt battery. Assuming negligible internal resistance in the battery, the current in the 16 ohm resistor will be A. 0.20 A. B. 0.5 A. C. 1.0 A. D. 12 A. E. 0.16 A.

A. 0.20 A.

The efficiency of a Carnot engine is 46%. What will be the temperature of the cold reservoir if the temperature of the hot reservoir is given as 510°C. A. 150°C B. 423°C C. 275°C D. 237°C

A. 150°C

An iPod uses 3.7 volts with direct current of 865 milliamps. What is the equivalent resistance of the entire iPod system? A. 4.3 ohms B. 1 ohm C. 3200 ohms D. 8.4 ohms

A. 4.3 ohms

Two very small spherical metal objects, each with 1 Coulomb of charge, are brought together in a vacuum so that the separation distance between their centers is 1 mm. What is the force of repulsion between the two objects? (Coulomb's constant is k=9.0 × 109 N.m2/C2.) A. 9 × 1015 N B. 9 × 1012 N C. 9 × 1014 N D. 9 × 1013 N

A. 9 × 1015 N

You have a set of 14 metal weights strung together by nylon fishing line at equal intervals. Each has a weight of 0.20 N. You suspend this array from the ceiling. Which part of the array has the greatest tension in the fishing line? A. Above weight 1 B. Between weights 1 and 3 C. Exactly at weight 7 D. Just above weight 14

A. Above weight 1

Why couldn't you use an electric motor to turn an electrical generator that in turn provides the electrical energy for the motor? A. No energy converter is 100% efficient B. Yes, you can do this C. Motors require AC and generators produce DC

A. No energy converter is 100% efficient

This sketch shows a bar magnet in a loop of wire with the bar perpendicular to the plane of the loop. The left-hand side shows the magnet being spun around its long axis while on the right side the magnet is turned end-over-end. Which case creates a larger induced current in the loop? A. The right-hand side B. The left-hand side C. Neither situation produces an induced current D. The induced current is the same in each case and is not zero

A. The right-hand side

In outer space, you observe a straight stream of electrons flowing past you at 14.5 miles per second, about the same speed that Mars moves on its orbit around the sun. You maneuver your spacecraft to face the current so that the electrons are moving from left to right and so that you are 10 m from the stream. In what direction does a compass needle point? A. UP B. DOWN C. LEFT D. RIGHT E. You observe no magnetic field

A. UP

When you shuffle your feet on a carpet on a dry day, you can accumulate a charge. The fact that you accumulate a charge means that the carpet is A. an insulator, because if it weren't, the charge would immediately leave you. B. an insulator, because only insulators can be charged by contact. C. a conductor, because charge cannot leave an insulator and move to you. D. a conductor, because conductors always have extra electrons.

A. an insulator, because if it weren't, the charge would immediately leave you.

Think of a closed rectangular loop of wire around the edge of a horizontal page. A magnetic field perpendicular to the page points upward and increases in strength in a certain time. During this time the conventional current induced in the loop will be A. clockwise. B. counterclockwise. C. zero. D. continually changing direction.

A. clockwise.

In a laptop computer, the power converter plugs into the wall's AC outlet and it plugs into the computer's DC power jack. The direct current is composed of A. electrons moving in the wire. B. protons moving through the wire. C. both protons and electrons moving through the wire in the same direction. D. exactly one half of the voltage of the AC that operates the power converter.

A. electrons moving in the wire.

Compared to the magnitude of the charge on a proton, the magnitude of the electrical charge carried by an electron is A. exactly the same. B. about the same. C. only 1/2 as large. D. only 1/3 as large.

A. exactly the same.

Heat is a form of energy, and it has long been known that heat energy will naturally flow A. from hot to cold objects B. from cold to hot objects. C. from solids to liquids, but only when the solid is melting. D. from liquids to solids, except when the solid is melting.

A. from hot to cold objects

A vibrating guitar string has exactly one antinode in the middle of the string and two nodes at the end. You have produced an oscillation of the string at its A. fundamental frequency. B. first harmonic frequency. C. second harmonic frequency. D. third harmonic frequency

A. fundamental frequency.

As a wave passes from one medium into another, it often happens that its speed increases with no change in frequency. Under these circumstances, the wavelength A. increases. B. decreases. C. stays the same.

A. increases.

When the temperature of the air in a balloon is raised, the volume of the balloon A. increases. B. stays the same. C. decreases.

A. increases.

As a given thundercloud's base elevation gets lower and lower, the possibility of lightning strike A. is greater, because the electric field strength increases. B. is less, since the electric field gets weaker. C. is unchanged, because the thundercloud has not polarized.

A. is greater, because the electric field strength increases.

It is an advantage for an automobile engine to run at a high temperature because A. its efficiency is higher since the temperature difference is what dictates efficiency. B. gasoline only ignites under high temperature conditions. C. a high operating temperature cools off the fuel before ignition. D. it allows the use of lighter engine components made from aluminum.

A. its efficiency is higher since the temperature difference is what dictates efficiency.

Suppose an audible sound wave were being produced at a frequency of 800 cycles per second. If the amplitude were doubled, the sound would become A. louder. B. softer. C. higher in pitch. D. lower in pitch.

A. louder.

Our model for explaining the electrical interaction between charged objects A. postulates that an electric field surrounds each charged object. B. makes sense only at very high speeds. C. depends on the existence of three kinds of charge. D. depends very strongly on the mass of the two objects.

A. postulates that an electric field surrounds each charged object.

Whenever a gas is compressed, A. work must be done on the gas. B. its internal energy must get smaller. C. heat must leave the gas. D. the temperature of the gas must get smaller.

A. work must be done on the gas.

One ampere is equivalent to A) 1 J/s. B) 1 C/s. C) 1 N/C. D) 1 V/m. E) 1 ohm/volt.

B) 1 C/s.

A household circuit rated at 120 volts is protected by a fuse rated at 10 amps. What is the maximum number of 100 watt light bulbs which can be lit simultaneously in parallel in this circuit without blowing the fuse? A) 4 B) 8 C) 12 D) 20 E) 24

B) 8

n many ways, an electric circuit is like the plumbing system in your home. The voltage on an electric circuit corresponds to the ________ in a plumbing system. A) trap B) pressure C) faucet or valve D) drain

B) pressure

The speed of electromagnetic waves in air is 3.0 × 108 m/s. What is the wavelength of FM radio waves having a frequency of 3.0 × 108 Hz? A. 0.333 m B. 1.0 m C. 3.0 m D. 6.0 m E. 10 m

B. 1.0 m

If two metal balls each have a charge of -10-6 C and the repulsive force between them is 1 N, how far apart are they? (Coulomb's constant is k=9.0 × 109 N.m2/C2.) A. 9.5 m B. 9.0 mm C. 9.5 cm D. 0.9 m

B. 9.0 mm

The correct expression for magnetic flux through area A, where B is a constant magnetic field and A is an area perpendicular to the field, is A. B/A. B. B × A. C. B + A. D.A/B. E. 1/(B × A).

B. B × A.

Two identical objects, one light colored and the other dark colored, are at the same elevated temperature, 50°C. You now place them in a dark, much cooler room. Which object will reach the room's temperature first? A. The light colored object B. The dark colored object C. Both reach room temperature at same time D. As strange as it seems, neither object will ever reach room temperature because energy conservation prevents the loss of energy

B. The dark colored object

Absolute zero is the temperature A. on the coldest day recorded at Nome, Alaska. B. at which an ideal gas would exert zero pressure. C. of the freezing point of water. D. of the boiling point of liquid helium.

B. at which an ideal gas would exert zero pressure.

A reversible engine is one that A. does no net work. B. causes no increase in net entropy. C. generates no net heat. D. acts as a refrigerator.

B. causes no increase in net entropy.

A positive charge is fixed at the origin. A negative charge is moved along the x-axis from x = 50 cm to x = 10 cm. The potential energy of the system A. does not change. B. decreases. C. increases.

B. decreases.

When a wave crosses from one medium into another in which the wave speed is lower, the frequency is unchanged. The wavelength A. increases. B. decreases. C. stays the same.

B. decreases.

In one cycle of any heat engine A. the net heat flow is zero. B. the internal energy of the engine does not change. C. more heat flows from the engine than enters the engine. D. the net work done is larger than the heat exhausted.

B. the internal energy of the engine does not change.

An ideal transformer is used to either increase or decrease the voltage in an AC circuit. When the output voltage is greater than the input voltage of a transformer then A. the power output depends on the ratio of turns in the primary and secondary. B. the power output is the same as the power input. C. the power output is larger than the power input. D. the power output is smaller than the power input.

B. the power output is the same as the power input.

If the resistance in a circuit using an ideal (no internal resistance) battery is increased, then A. the current coming out of the battery does not change. B. the voltage difference maintained by the battery does not change. C. the power output of the battery does not change. D. All of these choices are correct

B. the voltage difference maintained by the battery does not change.

Electromagnetic waves are generally A. longitudinal waves. B. transverse waves. C. a 50/50 combination of transverse and longitudinal waves. D. standing waves.

B. transverse waves.

When playing tennis, if you hit the ball off of the top end of the racket, an uncomfortable standing wave vibration is produced in the racket. This wave is A. longitudinal. B. transverse. C. both longitudinal and transverse. D. neither longitudinal nor transverse.

B. transverse.

Three different resistance lightbulbs are connected to a 120-V outlet. The most power will be consumed by the circuit A. when the bulbs are in series. B. when the bulbs are in parallel. C. when the least resistive bulb is in parallel with a series of the other two. D. when the most resistive bulb is in parallel with a series of the other two. E. The arrangement is unimportant because the voltage is the same in all cases.

B. when the bulbs are in parallel.

On a day when the speed of sound in air is 340 m/s, what will be the wavelength of sound of frequency 227 Hz? A. 227 m B. 3.0 m C. 1.5 m D. 0.67 m E. 0.33 m

C. 1.5 m

The south pole of a bar magnet is moved toward a short helical coil of wire (solenoid) along the axis of the coil. The coil has 100 turns and the ends of the coil are connected to form a closed circuit. If the coil is replaced with a single loop of the same type of wire, and the magnet is moved exactly as before, the current induced in the loop is A. the same as in the coil. B. zero in both cases. C. 100 times smaller. D. 100 times larger.

C. 100 times smaller.

An organ pipe of length 3.0 m has one end closed. The longest and next-longest possible wavelengths for standing waves inside the pipe are A. 6 m and 3 m. B. 12 m and 6 m. C. 12 m and 4 m. D. 9 m and 6 m. E. 3 m and 1.5 m.

C. 12 m and 4 m.

The voltage drop across a resistor is 4.0 V for a current of 1.0 A in the resistor. What is the current that will produce a voltage drop of 8.0 V across the resistor? A. 0.33 A B. 1 A C. 2 A D. 0.50 A

C. 2 A

Consider horizontal parallel plates with a fixed potential difference. The upper plate has a voltage difference of 30 V with the lower plate, and they are separated by 3 cm. You move the two plates carefully to a separation of 4 cm. What is the strength of the electric field between the plates? A. 3000 volts/meter B. 1000 volts/meter C. 750 volts/meter D. 7.5 volts/meter

C. 750 volts/meter

Which of the following units is not an energy unit? A. Joule B. Kilowatt-hour C. Horsepower D. Kilocalorie E. Calorie

C. Horsepower

Which general pattern holds for various excited states in standing waves on a rope or string fixed at both ends? A. Where the nodes are, you also find two antinodes B. Guitars and violins have antinodes only in even numbers: 0, 2, 4, and so on C. More antinodes mean shorter wavelengths D. Standing waves involve the interference of waves traveling in the same direction

C. More antinodes mean shorter wavelengths

You see a positively charged helium ion in space, and it is at rest with respect to your spacecraft. Since you are studying for the final exam, you decide to experiment. You slowly push the N pole of a bar magnet closer to the helium ion. What happens to the helium ion? A. It experiences a magnetic force and moves off B. It depends on whether it is a positive ion or a negative ion C. Nothing happens, because the ion is not moving

C. Nothing happens, because the ion is not moving

On a cold winter's morning, you awake and step out of bed. One foot is on the tile floor and the other is on a rug on the floor. Which statement is true? A. The tile feels colder because it is smoother than the rug B. The tile feels colder because it is connected to the cold ground outside C. The tile feels colder because it conducts heat more rapidly away from your foot D. The tile feels colder because it cannot absorb water like the rug can

C. The tile feels colder because it conducts heat more rapidly away from your foot

Which of these lists is in order of increasing wavelength? A. Second-harmonic, third harmonic, fourth harmonic B. First harmonic, second harmonic, fundamental C. Third harmonic, second harmonic, first harmonic D. First harmonic, second harmonic, third harmonic

C. Third harmonic, second harmonic, first harmonic

A positively charged ping pong ball is sitting stationary on the floor in the center of a room. There is also a constant, uniform magnetic field in the room that points toward the ceiling. If I now start the ball rolling toward the back of the room, the resultant motion of the ball, as observed from the ceiling, will be A. a diagonal straight line toward the left back corner of the room. B. a diagonal straight line toward the right back corner of the room. C. a horizontal, clockwise circle. D. a horizontal, counterclockwise circle. E. a straight line in the original direction of motion.

C. a horizontal, clockwise circle.

Entropy is A. another term for heat. B. a quantity that is conserved in any thermal process. C. a quantity that increases as the disorder of a system increases. D. something that never locally decreases in any process.

C. a quantity that increases as the disorder of a system increases.

A Carnot engine is A. equivalent to the gasoline internal combustion engine. B. currently in production for the new generation of imported cars. C. a theoretical engine having the highest possible efficiency for the temperatures involved. D. one that would violate the second law of thermodynamics.

C. a theoretical engine having the highest possible efficiency for the temperatures involved.

Comparing the electrostatic force and the gravitational force we can say that A. both have the same dependence on distance, both involve attraction and repulsion, but the gravitational force is stronger. B. both have the same dependence on distance, both involve attraction and repulsion, but the electrostatic force is stronger. C. both have the same dependence on distance, the electrostatic force can be either attractive or repulsive while the gravitational force is only attractive, and the electrostatic force is stronger. D. both have the same dependence on distance, the electrostatic force can be either attractive or repulsive while the gravitational force is only repulsive, and the electrostatic force is weaker. E. the electrostatic force falls off more rapidly with distance, the electrostatic force can be either attractive or repulsive while gravitation is only attractive, and the electrostatic force is stronger.

C. both have the same dependence on distance, the electrostatic force can be either attractive or repulsive while the gravitational force is only attractive, and the electrostatic force is stronger.

Hot cider is poured into a metal cup. Shortly thereafter the handle of the cup becomes hot. This is due to the process of A. radiation. B. convection. C. conduction. D. It will remain the same if the work done exceeds the heat added.

C. conduction.

If an electron moves in a magnetic field, A. it always feels a force. B. it only feels a force if its velocity vector is parallel (or antiparallel) to the direction of the magnetic field. C. it only feels a force if its velocity vector is not parallel (or antiparallel) to the direction of the magnetic field. D. it does not feel a force if it is in motion, only if stationary.

C. it only feels a force if its velocity vector is not parallel (or antiparallel) to the direction of the magnetic field.

Magnetic fields affect A. neither electric charges in motion nor electric charges at rest. B. both electric charges in motion and electric charges at rest. C. only electric charges in motion. D. only electric charges at rest.

C. only electric charges in motion.

A metallic object has a net charge on it. For steady state conditions, the excess charge is A. spread evenly throughout the object. B. in the center of the object. C. only on the surface. D. on the bottom of the object.

C. only on the surface.

In the southern hemisphere, the north pole of a compass needle A. points toward the south geographic pole because there is a south magnetic pole there. B. points toward the south geographic pole because that is the nearest magnetic pole. C. points away from the south geographic pole because there is a north magnetic pole there. D. spins aimlessly because the north geographic pole is beyond the horizon.

C. points away from the south geographic pole because there is a north magnetic pole there.

A 12 ohm resistor and a 24 ohm resistor are connected in parallel across a 6.0 V battery. The correct statement from the following is A. the current is the same in each resistor. B. the power dissipated is the same in each resistor. C. the voltage difference between the ends of each resistor is the same. D. the larger current is in the larger resistor.

C. the voltage difference between the ends of each resistor is the same.

A refrigerator that would transfer heat from a cold body to a hotter body without work being done would violate __________________ statement of the second law of thermodynamics.

Clausius's

The transfer of heat from a furnace to the house through ducts is by the process of _________________.

Convection

A point charge creates the electric field shown. At which of the points would the potential energy of a positive test charge have the largest value? A B C D

D.

Two equal charges repel one another with a force of 4.0 × 10-4 N when they are 10 cm apart. (Coulomb's constant is k=9.0 × 109 N.m2/C2.) If they are moved until the separation is 5 cm, the repulsive force will be A. 0.25 × 10-4 N. B. 1.0 × 10-4 N. C. 4.0 × 10-4 N. D. 16 × 10-4 N. E. 64 × 10-4 N.

D. 16 × 10-4 N.

The alternating current in wide use in homes in North America is 60 cycles per second, or 60 Hz. How many times per minute does this current reverse its direction of travel? A. 60 times B. 120 times C. 3600 times D. 7200 times E. None of these choices are correct

D. 7200 times

The temperature of 100 g of water is to be raised from 10°C to 90°C. The energy needed to do this is about A. 1 × 103 cal. B. 5 × 103 cal. C. 6 × 103 cal. D. 8 × 103 cal. E. 5.4 × 104 cal.

D. 8 × 103 cal.

Which of these is characteristic of an ideal (Carnot) heat engine? A. It does not create waste heat B. It cannot be used to cool a house C. It creates more energy than it consumes D. It causes no increase in entropy

D. It causes no increase in entropy

Water freezes at 273 on the ________ scale. A. Fahrenheit B. Celsius C. Rankin D. Kelvin E. Vernier

D. Kelvin

An electron situated near another electron would feel A. an attractive magnetic force. B. an attractive electrical force. C. a repulsive magnetic force. D. a repulsive electrical force. E. no forces from the other electron.

D. a repulsive electrical force.

An inventor has created a heat engine that extracts energy from geothermal hotspots and geysers like Old Faithful at Yellowstone National Park. She claims to turn all of the geothermal energy into work. Such a device is A. a violation of the first law of thermodynamics. B. consistent with Clausius's statement of the second law of thermodynamics. C. only possible for a Carnot cycle. D. a violation of Kelvin's statement of the second law of thermodynamics.

D. a violation of Kelvin's statement of the second law of thermodynamics.

A power rating printed on a lightbulb assumes a voltage of 120 V is applied to the bulb. If two 100 W bulbs are connected in series to a 120 V source, A. no current will pass through the bulbs. B. each bulb radiates 100 W. C. each bulb radiates more than 100 W. D. each bulb radiates less than 100 W.

D. each bulb radiates less than 100 W.

Electric heaters can operate at efficiencies very close to 100%. This does not contradict the fact that Carnot engines are the most efficient heat engines because A. electric heaters have very low temperature exhaust. B. electric heaters reduce the total entropy of a room. C. Carnot engines cannot be used to heat things. D. electric heaters are not heat engines.

D. electric heaters are not heat engines.

A fast train approaches a car waiting at a grade crossing and sounds its horn. A person in the car will notice that, compared to what it would be if the train were at rest, the horn sound's A. wavelength appears to be the same. B. wavelength appears to be longer. C. frequency appears to be lower. D. frequency appears to be higher.

D. frequency appears to be higher.

Toasters have wires in them that heat up to warm the items placed inside. For the toaster to work properly, these wires must A. be connected to a very large voltage. B. have less resistance than the power cord. C. be connected to a tiny voltage. D. have more resistance than the power cord.

D. have more resistance than the power cord.

An engine that decreases the total entropy in the universe is A. a refrigerator. B. a Carnot engine. C. a heat pump. D. impossible.

D. impossible.

An example of a reversible process would be A. firing a bullet from a gun. B. quickly pouring hot water into colder water. C. striking a match. D. slowly pouring hot water into cold while allowing the beakers to achieve ambient temperature levels.

D. slowly pouring hot water into cold while allowing the beakers to achieve ambient temperature levels.

Waves on a particular string travel with a velocity of 10 m/s. A high-speed photograph shows that successive peaks are 0.40 m apart along the string. The frequency of the waves is A. 5 Hz. B. 10 Hz. C. 15 Hz. D. 20 Hz. E. 25 Hz.

E. 25 Hz.

Suppose the velocity of waves on a particular rope under a tension of 100 N is 12 m/s. If the tension is decreased to 25 N what will be the new velocity of waves on the rope? A. 48 m/s. B. 24 m/s. C. 18 m/s. D. 12 m/s. E. 6 m/s.

E. 6 m/s.

The unit for electromotive force (emf) is A. N. B. A. C. ohm. D. N/C. E. V.

E. V.

The amount of heat is often measured in calories. If I add 1 calorie of heat energy to 1 gram of water, the temperature of the water will A. decrease by 1°F. B. decrease by 1°C. C. stay the same, since water has a very high specific heat D. increase by 1°F. E. increase by 1°C

E. increase by 1°C

A process carried out at constant temperature is known as a(n) _________________ process.

Isothermal

When there is a changing magnetic flux through an electric circuit, the direction of the induced current in the circuit is determined by _____________ Law.

Lenz's

In the water flow analogy with an electric circuit the flow meter in the fluid circuit is analogous to the ________________ in the electric circuit.

ammeter

The internal energy of a system such as helium gas can be identified as the total mechanical energy of the ______________.

atoms

A resistor R is connected across a battery of negligible internal resistance. If the resistance of R is doubled, the current in R will be __________.

halved

Increasing the air temperature inside an organ pipe, neglecting any expansion of the pipe, will _________________ the frequency of the fundamental tone

increase

A negatively charged grain of soot released between the parallel plates of a capacitor moves leftward. The potential between the parallel plates _________ (indicate whether it increases, decreases, or stays the same) from right to left, and the potential energy of the negatively charged grain of soot _________________________ (indicate whether it increases, decreases, or stays the same) from right to left.

increases, decreases

A dry cell battery is no longer useful when its ___________________ (two words) becomes large.

internal resistance

In a certain region of space, lines of constant positive electric potential around a positive charge get farther apart as one moves to the right. The force on a negative charge in this region will point to the ____________________.

left

If a negatively charged rod is brought close to (but not touching) an initially neutral object, the object becomes polarized and has ___________ charge.

no

A one ohm, a two ohm, and a three ohm resistor are connected in parallel in an electric circuit: The resistor dissipating the most power will be the ____________ ohm resistor.

one

A drop of water dripping from the faucet in your kitchen is electrically neutral. A charged plastic hair comb can attract the drips and drops by the process of __________________.

polarization

When one kilogram of ice at 0°C is converted to the same amount of water at 0°C by adding heat, the change in entropy is _______________ (positive, negative, zero).

positive

Two parallel wires each carrying a current in opposite directions will __________________ one another.

repel

As the temperature of a wire increases, its ___________ also increases.

resistance

It is observed that a negatively charged grain of soot released between the parallel plates of a capacitor moves leftward. The direction of the electric field between the capacitor plates is __________________.

rightward

The product of the frequency of a periodic wave times its wavelength gives the _________________ of the wave.

speed

When heat is added to a solid object, the ____________ of the object must increase.

temperature

Negative charges feel a force __________ (indicate direction) values of higher electric potentials.

toward

In the water flow analogy with an electric circuit the pressure in the fluid circuit is analogous to ______________ in the electric circuit.

voltage