Unit 8 -AP Physics

In the formula Q = m × c × T, which quantity is measured in units of J/g·°C?

c

Energy transfer by convection is primarily restricted to

fluids

How is energy transferred as heat always directed?

from an object at high temperature to an object at low temperature

When you touch a cold piece of ice with your finger, energy flows

from your finger to the ice.

To which of the following is high temperature related?

high particle kinetic energy

Compared to a giant iceberg, a hot cup of coffee has

higher temperature, but less internal energy.

Which of the following normally warms up fastest when heat is applied?

iron

Your feet feel warmer on a rug than on your tile floor because your rug

is a better insulator than your tile.

The number of molecules in one mole of a substance

is the same for all substances

A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample?

it does not change

Place a kilogram block of iron at 40 degrees C into a kilogram of water at 20 degrees C and the final temperature of the two becomes

less than 30 degrees C.

Energy transferred as heat occurs between two bodies in thermal contact when they differ in which of the following properties?

temperature

Which of the following is proportional to the kinetic energy of atoms and molecules?

temperature

As the temperature of a substance increases, its volume tends to increase due to

thermal expansion

Which of the following is a form of kinetic energy that occurs within a molecule when the bonds are stretched or bent?

vibrational

Which of the following physical properties can be used to measure temperature using a thermometer?

volume

Heat is added to an open container of a liquid. The liquid is brought to its boiling point and half the liquid boils away. Which of the following graphs shows how the temperature changes with time in this period?

/----

How many atoms are there in a mole of Hydrogen (H2) gas?

1.20×10^24

A container of an ideal gas at 1 atm is compressed to one-third its volume, with the temperature held constant. What is its final pressure?

3 atm

5000 J of heat is supplied in one minute to 0.06 kg of a liquid at its boiling point of 85°C to convert it completely to vapor. Which of the following expressions gives the heat of vaporization of the liquid?

5000/0.06 J/kg

Steam burns are more damaging than burns caused by boiling water because steam

Choices A and B are both correct. (gives up additional energy when it condenses, has more energy per kilogram than boiling water.)

Which of the following is a direct cause of a substance's temperature increase?

Kinetic energy is added to the particles of the substance.

What happens when water at its melting point solidifies to ice without any change in temperature?

Latent heat is emitted.

Which of the following best describes the relationship between two systems in thermal equilibrium?

No net energy is exchanged.

A solid is heated at a constant rate until it reaches the vapor state. The temperature of the substance changes with time as shown in the graph below. Which part(s) of the graph indicate(s) that the substance exists in solid-liquid and liquid-vapor state?

PQ, RS

Which of the following is true during a phase change?

Temperature remains constant.

If energy is transferred from a table to a block of ice moving across the table, which of the following statements is true?

The ice is cooler than the table.

When a closed tin is heated, the pressure inside it increases. This happens because:

The molecules move faster and each molecule strikes the walls of the tin more often.

The fact that desert sand is very hot in the day and very cold at night is evidence that sand has

a low specific heat.

Objects that radiate relatively well,

absorb radiation relatively well

Substances absorb heat energy by the process of

all of these (Conduction, Convection, Radiation)

Pour a liter of water at 40 degrees C into a liter of water at 20 degrees C and the final temperature of the two becomes

at or about 30 degrees C.

Both the pressure and volume of a given sample of an ideal gas double. This means that its temperature in Kelvin must?

quadruples

A Thermos bottle has double glass walls with silver coating on the glass surfaces that face one another. The silver coating reduces the energy that is transferred by

radiation.

If the pressure acting on an ideal gas at constant temperature is tripled, its volume is

reduced to one-third.

According to the ideal gas Law, PV = constant for a given temperature. As a result, an increase in volume corresponds to a decrease in pressure. This happens because the molecules

strike the container wall less often.