Physics Conceptual Final

An ideal gas undergoes an isothermal process. Which of the following statements are true? (i) No heat is added to or removed from the gas. (ii) The internal energy of he gas does not change (iii) The average kinetic energy of the molecules does not change.

(ii) and (iii) only

When using the ideal gas law, which of the following rules must be obeyed?

Always use temperature in kelvins and absolute pressure

Which is possible: converting (i) 100 J of work entirely into 100 J of heat, (ii) 100 J of heat entirely into 100 J of work?

Both (i) and (ii) are possible.

A thermally isolated system consists of a hot piece of aluminum and a cold piece of copper. The aluminum and the cooper are in thermal contact. The specific heat of aluminum is more than double that of copper. Which object experiences the great amount of heat transfer during the time it takes the system to reach thermal equilibrium?

Both experience the same magnitude of heat transfer

An ideal gas undergoes an adiabatic expansion, a process in which no heat flow into or out of the gas. As a result,

Both the temperature and pressure of the gas decrease

What is the primary mechanism by which heat is transferred through a pot of soup being heated on the stove?

Convection

For objects at thermal equilibrium, which of the following is true?

Each is at the same temperature

Both beakers A and B in the figure contain a mixture of ice and water at equilibrium. Which beaker is the coldest, or are they equal in temperature?

Equal in temperature

When you put an ice cube in a glass of warm tea, which of the following happens?

Heat flows from the tea into the ice cube

Which of the following happens when a material undergoes a phase change?

Heat flows into or out of the material

On mole of an ideal gas in a sealed rigid contained is initially at a temperature of 100 C. The temperature is then increased to 200 C. The pressure in the gas

Increases by about 25%

Which temperature scale does NOT have negative values?

Kelvin temperature scale

An ideal gas undergoes an isothermal expansion from state A to state B. In this process

Q > 0, delta U = 0, W > 0

Rod A has twice the diameter of rod B, but both are made of iron and have the same initial length. Both rods are now subjected to the same change in temperature (but remain solid). How would the change in the rod's lengths compare?

Rod A= Rod B In thermal expansion the change in length is independent of the rod's diameter or cross-sectional area

In a mixture of the gases oxygen and helium, which statement is valid?

The helium atoms will be moving faster than the oxygen molecules, on average

A flat metal washer is heated. As the washer's temperature increases, what happens to the hole in the center?

The hole in the center of the washer will expand

A steel plate has a hole in it with a diameter of exactly 1.0cm when the plate is at a temperature of 20 C. A steel ring has an inner diameter of exactly 1.0 cm at 20 C. Both the plate and the ring are heated to 100 C. Which statement is true?

The hole in the plate and the opening in the ring get larger.

Which of the following does the internal energy of an ideal gas depend upon?

The internal energy depends upon its temperature

The temperature of an ideal gas increases. Which of the following is true?

The pressure, the volume, or both, may increase

The linear expansion of a material depends on which of the following?

The type of material, the length of the material, and the change in temperature of the material

If the pressure acting on a given sample of an ideal gas at constant temperature is tripled, what happens to the volume of the gas?

The volume is reduced to one-third of its original value

It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it is nighttime. The water is cold! The next day, you go swimming again during the hottest part of the day, and even though the air is warmer the water is still almost as cold. Why?

Water has a high specific heat (much higher than air) so its temperature remains fairly constant even though the surrounding air may experience large temperature fluctations.

As heat is added to water, is it possible for the temperature measured by a thermometer in the water to remain constant?

Yes, the water could be changing phase

Radiation is emitted

by any object not at 0 K. Radiation is emitted by all objects not at absolute zero

By which primary heat transfer mechanism does one end of a steel rod become hot when the other end is placed in a flame?

conduction

A typical thermos bottle has a thin vacuum space between the shiny inner flask (which hold a liquid and the shiny protective out flask), often stainless steel. The vacuum space is excellent at preventing

conduction and convection. The vacuum in a thermos prevents heat loss by these.

The first law of thermodynamics is usually written as Q = W + deltaU. You need to look at the signs carefully; some other disciplines (chemistry, for example) may use other signs, which implies other definitions of these quantities. Which physical law underlies the first law of thermodynamics?

conversation of energy

The first law of thermodynamics is usually written as Q = W + deltaU. You need to look at the signs carefully; some other disciplines (chemistry, for example) may use other signs, which implies other definitions of these quantities. The quantity Q is the _______ that is added to the system

heat

The first law of thermodynamics is usually written as Q = W + deltaU. You need to look at the signs carefully; some other disciplines (chemistry, for example) may use other signs, which implies other definitions of these quantities. The quantity delta U in the first law of thermodynamics is the changes in the _________ of the system.

internal energy

A gas is taken through the cycle illustrated in the pV diagram shown. Which path represents an isothermal process? A C B

path A to B

A gas is taken through the cycle illustrated in the pV diagram shown. Which path represents an isobaric process? A C. B

path B to C

A gas is taken through the cycle illustrated in the pV diagram. Which path represents an isochoric process? A C B

path C to A

The first law of thermodynamics is usually written as Q = W + deltaU. You need to look at the signs carefully; some other disciplines (chemistry, for example) may use other signs, which implies other definitions of these quantities. If heat is added to a system (Q > 0) and no change in internal energy of the system occurs (delta U = 0), then the system must do _______ work on the outside world.

positive

By which primary heat transfer does the Sun warm Earth?

radiation

Heat is

the amount of energy transferred between objects as a result of a difference in temperature

An ideal gas is in a sealed rigid container. The average kinetic energy of the gas molecules depends most on

the temperature of the gas. The temperature of the gas is a measure of the average kinetic energy of the gas molecules.

The rms speed of the molecules of an ideal gas

will increase as the temperature of a gas increases

The first law of thermodynamics is usually written as Q = W + deltaU. You need to look at the signs carefully; some other disciplines (chemistry, for example) may use other signs, which implies other definitions of these quantities. The quantity W in the first law refers to the _______.

work done by the system

In an isobaric compression of an ideal gas,

work is done on the gas.