Physics

A 100 Ohm, 200 Ohm, and 300 Ohm resistor are all connected in series to a 12 V battery. What is the potential difference drop across the 100 Ohm resistor?

2 V

In an adiabatic process, the first law of thermodynamics simplifies to:

(change of aka: little triangle) U= -W

The correct expression relating electric potential difference to the electric field, for point charges is:

(change of aka: little triangle) V= -E(change of aka: little triangle)

Which of the following equations represents Heisenberg's Uncertainty Principle?

(change of aka: little triangle) x (change of aka: little triangle) p= h/2pi

An engine is not functioning properly and does no work. What can you say about this from the first law of thermodynamics?

(change of:aka:little triangle) U= Q

What is the electrostatic force between two +0.25 C charges that are 0.25 m apart? (Coulomb's constant is 9.0 × 109 Nm2/C2)

+9.0 × 109 N

What is the electrostatic force between two +0.5 C charges that are half a meter apart? (Coulomb's constant is 9.0 × 109 Nm2/C2)

+9.0 × 109 N

How much pressure is needed to do 1000 J of work when changing a volume of gas by 0.1 m3?

10,000 Pa

An object is suspended in a liquid and the apparent weight is 20 N but it would normally weigh 200 N. What is the buoyant force on the object

180 N

If a resistor is connected to a circuit and 0.5 amps pass through it then the voltage is doubled. What would you expect the new current to be?

1 A

The height of the atmosphere is 100 km, roughly. The density of air has an average of 1.23 kg/m3. Assuming the acceleration of gravity is constant, estimate the pressure felt by a person at sea level?

1,200 kPa

A 100 Ohm, 200 Ohm, and 500 Ohm resistor are connected in parallel. What is the total current through the circuit, if the resistors are connected through a 60 V battery?

1.02 A

How many electrons pass by a point every second if a 0.200-amp current is flowing? (e = -1.602 x 10-19 C)

1.25 x 1018 e

Your hand is wrapped around a cold iron bar. Your hand has 1000 J of thermal energy before touching the bar and 900 J after holding the bar for a minute. How much energy has the bar gained in the time of contact?

100 J

A test charge is placed in an electric field of 40 N/C and experiences an electrostatic force of 10 N. What charge does the test charge carry?

2.5 x 10-1 C

Five, 100 Ohm resistors are all in parallel to each other. What is the equivalent resistance of the five resistors?

20 Ohms

What mass of water can be heated from 25.0° C to 50.0° C by the addition of 2825 J? (cwater = 4186 J/kg°C)

27 g

At what temperature does water freeze? Check all that apply.

273 K 32°F 0°C

How many joules are needed to vaporize 125 g of liquid water at 100°C? The latent heat of vaporization is 2258 J/g.

282,000 J

If a substance is changing temperature from below its melting point to above its melting point, how many calculations would you have to perform?

3

A test charge is brought into an electric field from a source charge of 4.5 x 10-8 C at a distance of 10 centimeters. What is the field strength at that distance?

4.1 x 104 N/C

A parallel plate capacitor has a separation distance of 2 mm and an area of 100 mm2. What is the capacitance? (ε0 = 8.85 x 10-12 C2/Nm2)

4.4 x 10-13 F

What is the de Broglie wavelength of a 1.22 kg discus moving at a speed of 12 m/s? (h = 6.626 x 10-34 J·s)

4.53 x 10-35 m

Convert 212°C to Fahrenheit.

413°F

What is the final temperature when 625 grams of water at 75.0° C loses 7.96 x 10^4 J? (cwater = 4186 J/kg°C)

44°C

How much work does a 75-Watt bulb do in 1 minute?

4500 Joules

A parallel plate capacitor has a charge of 1 x 10-6 C and potential of 1 V. What is the electric potential energy of the capacitor?

5 x 10-7 J

What is the de Broglie wavelength of a particle with a momentum of 1.11 x 10-10 kg·m/s? (h = 6.626 x 10^-34 J·s)

5.96 x 10-24 m

A circuit has one 123 Ohm resistor, one 145 Ohm resistor, and one 234 Ohm resistor, all in series. What is the equivalent resistance of the circuit?

502 Ohms

A 175 Ohm, 546 Ohm, and 22 Ohm resistors are all connected in series to a battery. Which one will have the largest drop in potential difference across it?

546 Ohm resistor

Convert 300°C to Kelvin.

573.15 K

A 100 Ohm, 200 Ohm, and 500 Ohm resistor are connected in parallel. What is the equivalent resistance of the three resistors?

59 Ohms

Convert 32°C to Fahrenheit.

90°F

Which are examples of entropy increasing? Check all that apply.

A solid becoming a liquid A liquid becoming a gas Wood burning in a fire

Why do you think blacksmiths must have such hot fires to forge steel?

Because metals absorb lots of heat, and so need a hot fire.

If you poke a hole in a water filled balloon, where should poke the hole to have the water leak out the fastest?

Bottom

What is the name of the method used to measure specific heat capacity?

Calorimetry

Which of these scientists is most known for their postulate that all matter can exhibit wave-like behavior?

De Broglie

A system has energy given to it, and the system uses a bit of that energy to do work on the environment. The internal energy must have:

Decreased

Decreasing the internal energy of a substance:

Decreases entropy in the substance

Which of these scientists is most known for their discovery of the photoelectric effect?

Einstein

The correct form of the expression relating mechanical work to work done on a gas is:

Fd=P(change of aka: little triangle)V

The equivalent resistance of two resistors in parallel is 10 ohms. Which are possible combinations that could lead to this equivalent resistance? Check any that apply.

Five, 50 Ohm resistors Three, 30 Ohm resistors Two, 20 Ohm resistors

Which of the following would transform heat into work? Check any that apply.

Four-stroke internal combustion Engine Hero's Engine Steam Engine

Heat transfer in calorimetry is always:

From hot to cold

An object is suspended halfway down to the bottom of a lake. What can you say about the forces according to Archimedes principle?

Fsubcase b = F subcase w

Negative heat indicates that:

Heat is lost

A 100 ohm resistor is connected in parallel to a 50 ohm resistor. Both of which are connected to a 12 V battery. What is the current through each resistor?

I100 = 0.12 A and I50 = 0.24 A

Entropy is always:

Increasing

An insulator can charge by: (Check any that apply.)

Induction Friction

When a substance absorbs or releases heat, the ______ changes.

Internal Energy

If you squeeze a gas inside of a cooler, meaning it cannot gain or lose heat, what must be true? Check all that apply.

Internal Energy increases Work done on gas is negative Temperature increases

At what point do the Celsius and Kelvin temperature scales have the same value?

Never

A scientist claims they have created a system that cools itself down, without any heat or work done. Your response to this is:

No way, ΔU=Q-W, and that is impossible

The effort to build an engine which is 100% efficient is:

Not Possible

What parameter is always the same in a parallel circuit?

Potential Difference

A child slides down a slide in the park and builds up electrons. When the parent picks the child up they feel a zap. Which statements below correctly describe this charging?

Sliding is charging by friction and zapping is charging by conduction.

If you have several substances that look similar, which characteristic would enable you to precisely distinguish what they are made of?

Specific Heat Capacity

When a solid changes immediately to a gas, this process is called:

Sublimation

Throwing a ball around in the cold weather can hurt more because:

The air density inside the ball increases, therefore making it feel more solid

A small resistor is connected to a 12 V battery. A second resistor of REALLY high resistance is added to the series circuit. How does this affect the current?

The current of the entire circuit is lowered.

A single resistor is connected to a power supply. Periodically, another resistor is added to the circuit, in series, and then another, and so on over some time. Over time, you would expect:

The current would decrease over time.

The actual atmospheric pressure at sea level is 102 kPa. Why is pressure at higher altitudes different? Choose all that apply.

The edge of the atmosphere is not well-defined. the acceleration of gravity changes as you get further away from the surface the density of air changes as you get further away from the surface

Which statement best describes the electrostatic force and the electric field?

The electrostatic force requires two charges and the electric field is intrinsic to one charge.

When checking your tire pressure, why is it a good idea to do so after driving around for a bit?

The tires will be warmer and closer to the normal operating pressure.

The study of heat and energy is the study of:

Thermodynamics

When two objects are in thermal equilibrium with a third object, then:

They are in thermal equilibrium with each other.

Where is the Fahrenheit temperature scale most commonly used?

U.S.A.

An equivalent expression for current through several resistors in series is:

V/R1= V/R2= V/R3...

A valid expression for the potential difference across each of 3 resistors in series is:

V1+V2+V3=Vt

Three resistors are in parallel and connected to a battery. It is known that R1 > R2 > R3. Which statement is correct regarding the voltage drop across each resistor?

V1=V2=V3=Vt

Which process generally requires more energy?

Vaporization

Ten identical light bulbs are connected in parallel to a battery. What can be said of the voltages and currents for each light bulb?

Voltages and currents are all equal

You slowly crush a full can of juice such that the temperature of the juice does not change, what is changing in this situation? Check all the apply.

Volume Pressure

A blacksmith places a piece of hot iron in cold water because:

Water can absorb lots of heat energy quickly.

Heat engines are devices that turn heat into:

Work

Describe why you should never touch your tongue to a cold piece of metal. Be sure to include the terms energy, transfer, conduction, and saliva in your response.

You should never touch your tongue to a cold piece of metal because since the metal is a conductor, meaning that it transfers heat very fast, the metal is taking the heat energy from your tongue quickly. You are also in conduction because your tongue is in contact with the metal. Your tongue might get stuck because your saliva will freeze with the metal because the temperature will change- my own example- change it in the future

What determines whether electrons will move when charging by friction?

electron affinity

Assuming you have a point charge in a powerful and constant electric field, what is the relationship between the electric field and the electric potential energy?

not: E=PE electric/q

What requires the most energy?

not: Freezing 0.5 kg of ice

During a phase change, what properties change?

not: Heat

If you disconnect one branch of a parallel circuit, what will happen to the remaining branches?

not: The voltage on each branch stays the same and the current decreases.

Conduction can only happen when objects are in:

thermal contact

When two objects are at the same temperature, they are in ________.

thermal equilibrium

The Celsius and Kelvin scales are useful because:

they are based off natural physical phenomena.

The zeroth law of thermodynamics relates to:

three objects being in thermal equilibrium

Calculate the pressure at the bottom of the Mariana Trench, which has a depth of roughly 11,000 meters. The density of water is 997 kg/m3.

108,000 kPa

How much power does a 12.0-volt circuit use that has a resistance of 12.0 Ω?

12.0 W

An engine with 100 J of heat compresses gas in a cylinder with 50 J of work. What is the change in internal energy of the gas?

150 J

The internal energy of a balloon changes by 100 J. The work done on the environment around it is 70 J. How much heat does the balloon gain?

170 J

A car motor releases 700 J of energy into the cooling system. It is a combustion motor which is 50% efficient. What amount of work could you expect from the motor?

not:350 J

The human body may seem to be a perfectly efficient system, but there is a source of energy input, to keep a human body running at maximum efficiency. This energy comes from:

Food

A roller coaster passes the summit and then reaches the bottom of its run at high speed. An equation which could describe this process is:

GPE = KE + Q

You are trying to construct a power device, but cannot seem to find enough electrons to flow. How might you solve this?

Grounding

Which of the below are types of energy? Check all that apply.

Heat Kinetic Potential

The force between two charges has been decreased by a factor of 9. What could have happened to cause this? Check any that apply.

One charge changed by 1/9. The distance is 3 times greater The charges changed by 1/3 each. not certain on these answers

You are the lucky person who witnesses a miracle: You have placed water into your freezer and witnessed it becoming ice. Entropy increase has been reversed. Where did the entropy go?

Out the freezer exhaust

Show that the value for both the Celsius scale and the Fahrenheit scale would be the same at -40°. Show all of your work to receive full credit.

Plug -40° into the equation either equation and work the problem.TC=59⋅(TF−32)TC=59⋅(−40−32)TC=59⋅(−72)TC=−40Thus, -40°C = -40°F

Which is a valid expression for the equivalent resistance for multiple resistors in series?

Rt=R1+R2+R3...

If you wanted to melt ice, then heat it up, and get the water to just barely vaporize, how many equations would you need to solve for the energy used in this procedure?

not: 4

A can of gas has a pressure of 101,325 Pa and the volume changes from 0.01 m3 to 0.005 m3. What is the work done?

not: 507 J

A physics student claims that if you connect a resistor to a 12 V battery, then the potential difference drop across the resistor is exactly 12 V. This statement is suspect because:

not: The circuit must be closed for this to occur.

Two balls are close together. They have the same charges, the same masses, and the charges are the same as the masses. Which force is stronger?

not: They are equal

When is it possible to have a negative electrostatic force, and a positive electric field?

not: When a positive test charge is placed near a negative charge.

When you use up a can of compressed air to clean your computer, the can gets cold. This is an example of an _____________ process.

not: adiabatic

A 50 kg child sits on the left side of the bathtub. A small toy boat of 0.5 kg is on the right side of the bathtub. Which part of the bathtub has the greatest pressure?

not: left maybe?: bottom

You blow up a balloon, then squeeze it, and then the balloon pops back out after you finish squeezing it. What are the signs of the work being done on the air in the balloon, in chronological order?

not: negative, positive, negative

You give a 1 kg piece of ice at 0°C 10,000 J of heat energy. How much ice is left after this heat transfer? (Lf = 3.33 x 105 J/kg, cwater 4186 J/kg°C)

not:940 g

What happens at zero Celsius?

water freezes

Which temperature has the most kinetic energy?

-10°C

A metal ball is able to pass through a metal ring, just barely. How can one increase the size of the ball, without changing the mass of the ball, so that it will no longer pass through the ring?

Heat the ball to make it bigger.

To open a jar that has a lid stuck to it, one should:

Heat the lid.

(change in: aka: little triangle)U= Q is indicative of an ______________ process.

Isovolumetric

Which expression best fits how current is defined in a parallel circuit?

It=I1+I2+13

The unit for measuring heat is:

Joules

Which of the following are examples of resistors in a circuit? (Check all that apply

Light Bulb Fan Toaster

Which of the following are true? Select all that apply.

Light exhibits wave characteristics when interacting with solid matter. All matter has a specific de Broglie wavelength. Light exhibits particle characteristics when interacting with solid matter. (did not get these all right)

The heat needed to raise the temperature of an object depends on which parameters? Check all the apply.

Mass Temperature

Which ranking correctly places the charges of subatomic particles in order from positive to negative charge?

Protons, Neutrons, Electrons

One 10 Ohm resistor, R1, is connected to a 12 V battery. A second 10 Ohm resistor, R2, is added in series. What is the potential difference across each resistor?

R1 = 6 V and R2 = 6V

Three resistors are in parallel and connected to a battery. It is known that R1 > R2 > R3. Which resistor will have the largest current flowing through it?

R3

Which of the following definitions of work are accurate? Choose all that apply.

W=Fd W=P(change of:aka triangle)V

A test charge is placed in an electric field which is pointing towards a charged ball. The test charge is pushed away from the charged ball. This situation describes:

a negative test charge and a negatively charged ball

An electron is separated from another point charge by a distance of 5 centimeters. The electrostatic force between them is -9.24 x 10-26 C. What is that point charge? (Coulomb's constant is 9.0 × 109 Nm2/C2; e = -1.602 x 10-19 C)

a proton

If electric potential energy is the result of the interaction between two charges, then electric potential difference is applicable to:

a single charge

ΔU=W is indicative of a ___________ process.

adiabatic

If you change the volume of a gas very quickly such that no heat is transferred to the environment, this would be an example of an:

adiabatic process

A cooking pot is sitting in a kitchen for several hours unused. Why does it feel cold when you touch it?

because metals take heat energy from your hand quickly.

Which of the following are properties of a liquid. Click all that apply.

cannot be easily compressed flows easily takes the shape of the container

Choose any that apply. One should check tire pressure regularly because the air in the tire can:

change volume due to temperature changes change density due to temperature changes

Capacitance can be defined as:

charge per change in electric potential

Grounding is an example of what method of charging?

conduction

Charging an object involves the moving of _____.

electrons

A student decides they need a cup of coffee. The energy lost as the coffee cools down is _____ the energy gained by the surrounding air.

equal to

Archimedes' principle states that the buoyant force of an object submerged in a liquid is ____________ the weight of the liquid it displaces.

equal to

Temperature is defined as:

how hot or cold something is

Bridges and sidewalks have regularly spaced cracks built into them because when it is hot, the cement:

increases its volume and needs space to grow into

What kind of charging does an electroscope model?

induction

Rubber is a type of _________.

insulator

You hike in the mountains all day, and finish ½ a bottle of water. You then drive to the valley below, which is at the same temperature, and see that the bottle of water is crushed a bit. This is an example of an _______ process.

isothermal

Two substances of different temperatures are brought into thermal contact. While the objects come to equilibrium, some heat is lost to the environment. How would that affect the final temperature?

it would be lower

An unknown substance requires 32340 J of heat to melt. If the substance has a mass of 1.32 kg, what is the unknown substance?

lead

Convection is the transfer of heat energy via:

liquids or gases

Choose any that apply. Most objects that are heated have a:

lower density higher volume

Water has a density of 997 kg/m3, liquid mercury has a density of 13,560 kg/m3 and cooling oil has a density of roughly 930 kg/m3. Rank the liquids in terms of top to bottom if they were placed in the same container.

oil, water, mercury

Which of the following would be an example of charging by induction?

polarizing a rod by bringing a charged object close to it

According to the uncertainty principle, you cannot know the _____ and the _____ of a particle simultaneously with 100% accuracy.

position, momentum

A silly physics student leaves a can of soda in a hot car for a long period of time. When the student returns, the soda can has leaked out into the car. The best description for this situation is:

pressure buildup in an isovolumetric situation

If the uncertainty of the magnitude of momentum approaches zero, the uncertainty in the location ____.

remains constant

Which of the following would be an example of charging by friction?

rubbing a piece of fur on a balloon

A rock is placed at the bottom of a filled bathtub with area = 2 m2. The same rock is then placed in a graduated cylinder of the same depth of water and area of 0.02 m2. In which situation does the rock experience the greatest pressure from the water?

same pressure

An ice cube sitting on a piece of wood would melt:

slowly

When ink is poured into a hot cup of water it will:

spread throughout the water quickly.

Capacitance is best described as the ability to:

store electric potential energy.

A circuit has one 10 Ohm resistor and you want to drop the current by a factor of two. Which of the methods below would allow this? You could add: (Choose any that apply. )

ten 1 Ohm resistors another 10 Ohm resistor two 5 Ohm resistors

Which of the following are conductors? (Select all that apply).

tile metals

Click any that apply. Examples of heat conduction via radiation include:

toaster the sun a heat lamp

Which of the following would be an example of charging by conduction?

touching a charged comb to a neutral comb

Which of the following is evidence of static electricity? Mark all that apply.

two objects repel each other two objects attract one another a spark travels between two objects

Which substance contracts when the temperature increases from 0 to 4°C.

water

Moving a small positive test charge closer to a positive source charge requires:

work

Convert 100 K to Fahrenheit.

-280°F

In cooling down milk, the internal energy changes by -400 J. If -450 J of heat was absorbed by the fridge, how much work was done on the milk?

-50 J

Convert 212 K to Fahrenheit.

-78°F

If a parallel plate capacitor has the positive plate charged to +Q. What is the charge of the minus plate?

-Q

One expression for the electric potential energy on a test charge is:

-qEd

One electron is separated from another electron by a distance, d. The electrostatic force between them is +5.77 x 10-25 newtons. How far apart are they? (Coulomb's constant is 9.0 × 109 Nm2/C2; e = -1.602 x 10-19 C)

0.020 cm

A 10 Ω wire is connected to a 1.5 V battery. What is the current that flows through the wire?

0.15 amps

A 15 Ω wire is connected to a 3.0 V battery. What is the current that flows through the wire?

0.20 amps

A 100 Ohm, 200 Ohm, and 500 Ohm resistor are connected in parallel. These are then connected to 60 V battery. What is the current flowing through the 200 Ohm resistor?

0.30 A

A 50 Ohm resistor is in parallel to a 100 Ohm resistor which is in turn in parallel to a 500 Ohm resistor. What is the total current traveling out of a 10 V battery?

0.32 A

The current leaving a battery is 0.5 A. It travels through a 100 Ohm, 200 Ohm, and 300 Ohm resistors all in series. What is the current right before it comes back to the battery?

0.5 A

How many kilograms of water at 100.0°C can be vaporized if 1278900 J of heat are added to the water? (Lv = 2.26 x 106 J/kg)

0.566 kg

A piston has a volume change of 7 x 10-6 m3. Assuming atmospheric pressure is 101,325 J, what is the work needed to change the piston volume?

0.71 Pa

The specific heat of aluminum is 899 J/kg*C. How much aluminum is changed by 1.00°C assuming 1000. J of heat is added to the piece of aluminum?

1.11 kg

With what speed would a particle with a mass of 1.05 x 10-17 kg have to move if it had a de Broglie wavelength of 3.78 x 10-25 m?

1.68 x 108 m/s

A cylindrical copper wire has a resistance of 10 Ω across a 1-meter length. The resistivity of copper is 1.7 x 10-8 Ω-m. What is the cross-sectional area of the wire?

1.7 x 10-9 m2

Water has 10 times the specific heat capacity compared to iron. How much water would be needed to absorb the same amount of heat as a piece of iron?

1/10th the mass of iron

If you randomly shuffled a deck of 52 cards, what is the likelihood that they would come together in perfect order by number and suit?

1/52!

A cube of volume 10 m3 and mass of 100 kg is suspended in a fluid. Determine the density of the fluid.

10 kg/m3

A 1 x 10-9 Farad capacitor has a charge of 1 x 10-7 C. What electric potential is driving this capacitor?

100 V

Two, 100 Ohm resistors are connected in parallel to a 100 V power supply. You add two more 100 Ohm resistors in parallel to the first two. What are the voltages across the new resistors?

100 V

If 1000 J of heat energy is lost from a piece of hot metal which is placed into a cup of cool water, how much energy is gained by the water?

1000 J

What pressure if needed to do 101,325 J of work to change the volume of a gas from 3 m3 to 4 m3?

101,325 Pa

An engine is able to do 1000 J of work. How much heat would need to be added for it to be as efficient as an electric motor?

1250 J

A 122 Ohm, 232 Ohm, and 500 Ohm resistors are all connected in series with a 12 V battery. What is the current flowing through them?

14 mA

Given 1,000,000 J of energy, what is the maximum amount of gold you can melt? The latent heat of fusion for gold is 6.44 x 104 J.

15.5 kg

An engine is 34% efficient. What ratio of work to heat input is possible?

19/56

One kilogram of water at 45°C is mixed with 1.5 kg of alcohol at 20°C. What is the final temperature of the mixture? (cwater = 4186 J/kg°C, calcohol = 2400 J/kg°C)

33°C

How much work does a 60-watt bulb do in 1 minute?

3600 J

A test charge of +5e is brought into an electric field of strength of 5.0 x 10-5 N/C at a distance from the source of 10 centimeters. What is the electrostatic force on that test charge? (Coulomb's constant is 9.0 × 109 Nm2/C2; e = -1.602 x 10-19 C)

4.0 x 10-23 N

How much power does a 12-volt circuit use that has a 0.5-amp current flowing through it?

6.0 x 100 W

You provide 10 J of work on an electron over an electric field of 100 N/C. How far did you push the electron? The fundamental electric charge is 1.6 x 10-19 C.

6.25 x1017 m

A circular piston of radius 0.01 m is compressed by 0.02 meters. What is the change in volume of this compression?

6.3 x 10-6 m3

What is the de Broglie wavelength of a 2.89 x 10-28 kg particle moving at 3.00 x 108 m/s? (h = 6.626 x 10-34 J·s)

7.65 x 10-15 m

An engine uses 1 kJ of energy to run but is only 72% efficient. What is the useful work you can expect from the engine?

720 J

Which of the following charges are possible? Check all that apply.

8.35 x 10-19 C 1.67 x 10-19 C 3.34 x 10-19 C

An object of 1 m3 volume is suspended in the middle of the ocean. What is the buoyant force on the object? The density of water is 997 kg/ m3.

9,780 N

How much power does a 9.0-volt circuit use that has a 1.0-amp current flowing through it?

9.0 W

A boiler does 1 kJ of work and then the heat of the exhaust is measured to be 100 J. What is the efficiency of the boiler?

90%

A parallel plate capacitor of 1 x 10-6 C is connected to a 12 V battery. What is the ratio of area to separation distance of the capacitor? (ε0 = 8.85 x 10-10 C2/Nm2)

94

Aluminum is often melted down for recycling purposes. Assuming 1 kg of aluminum is at 20 deg C (room temperature), what is the minimum amount of heat needed to melt it to a liquid? The specific heat capacity of aluminum is 899 J/kg°C, the melting point is 660°C, and the latent heat of fusion is 3.97 x 105 J/kg.

972,000 J

What is the average temperature of the human body? Check all that apply.

98°F 37°C 98°F

An engine does 90 J of work and requires 450 J of energy to run each cycle. What type of engine is it most likely to be?

Combustion

Check all that apply. The mechanisms of heat transfer that need a medium are:

Conduction Convection

An electron is separated from another point charge by a distance of 8 centimeters. The electrostatic force between them is +3.61 x 10-26 C. What is that point charge? (Coulomb's constant is 9.0 × 109 Nm2/C2; e = -1.602 x 10-19 C)

an electron

A piece of ice is melting on a table. How does the temperature just before melting compare to the temperature just after melting?

before = after

Which of the following is an example of grounding?

bringing a charged rod in contact with the Earth

Which processes are increases in entropy in a substance? Check all that apply.

burning wood boiling water

A 65.0 g piece of iron at 525° C is put into 635 grams of water at 15.0° C. What is the final temperature of the water and the iron? (cwater = 4186 J/kg°C, ciron = 412 J/kg°C)

not: 20.1°C

1000 J of energy is given to a balloon via a heating device. Assuming the pressure is a constant 101,325 Pa, what is the final volume of the balloon, assuming it started at 0.001 m3?

not: -0.011 m3

One electron is separated from another electron by a distance, d. The electrostatic force between them is +9.24 x 10-26 newtons. How far apart are they? (Coulomb's constant is 9.0 × 109 Nm2/C2; e = -1.602 x 10-19 C)

not: 0.050 cm

1 x 1015 electrons are pushed through a 10 Ω wire in one minute. What is the voltage of the power source? (e = -1.602 x 10-19 C)

not: 1.6 x 10-4 V

How many electrons pass by a point every second if a 0.400-amp current is flowing? (e = -1.602 x 10-19 C)

not: 1.60 x 1018 e

If a circuit is connected and the power over the resistor is P. Doubling the current through the resistor will change the power by what factor?

not: 1/2

A hydraulic lift needs 1000 kPa to lift a car that creates a pressure of 100 kPa on the other side. What is the pressure of the liquid in the lift that is under the car?

not: 100 kPa

Five, 600 Ohm resistors are connected in series to a 1000 V power supply. What is the potential difference across the third resistor?

not: 1000 V

You have 1 kg of water and you want to use that to melt 0.1 kg of ice. What is the minimum temperature necessary in the water, to just barely melt all of the ice? (Lf = 3.33 x 105 J/kg, cwater 4186 J/kg°C)

not: 100°C

A hot air balloon is heated so that the change in internal energy is 100 J. If the heat lost to the environment is only 20 J, what is the work done on the atmosphere?

not: 180 J

A parallel plate capacitor has a set area but can change the distance between the plates. If you double distance between the plates, you would expect the capacitance to change by a factor of:

not: 2