EPS EXAM #2
The lowest temperature possible in nature is
-273°C
Two charges separated by 1 m exert a 1-N force on each other. If the charges are pulled to a3-m separation distance, the force on each charge will be
0.11 N
It is possible to totally convert a given amount of mechanical energy into heat.
True
In the mountains, water boils at
a lower temperature than at sea level.
Electrons are made to flow in a wire when there is
a potential difference across its ends.
The pupil of your eye is designed to be an
absorber of radiant energy
When a solid is changed to a liquid phase, the solid
absorbs energy
Surrounding every moving electron is
an electric field and a magnetic field
Rapid changes of a magnetic field induces
an electric field.
An electron and a proton
attract each other.
Hot water will cool to room temperature faster in a
black pot
Which force binds atoms together to form molecules?
electrical
When water at 4°C is heated it expands. When water at 4°C is cooled, it
expands
Energy transfer by convection is primarily restricted to
fluids
If you pick up a snowball, energy flows
from your finger to the ice
To say that an object is electrically polarized is to say
its charges have been rearranged.
When two lamps are connected in parallel to a battery, the electrical resistance that the battery senses is
less than the resistance of either lamp.
A wire that carries an electric current
may be electrically charged
A good reflector of radiation is a
poor absorber of radiation.
Increased air pressure on the surface of hot water tends to
prevent boiling
A positive ion has more
protons than electrons
A main difference between gravitational and electric forces is that electrical forces
repel or attract
In an electric circuit, the safety fuse is connected to the circuit in
series
Magnetism is due to the motion of electrons as they
spin on their axes and move around the nucleus
When heat is added to boiling water, water temperature
stays the same
It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling
supports this common knowledge
Heat energy travels from an object with a high
temperature to an object with a lower temperature.
Sparks from a very hot Independence Day sparkler won't harm you is because
the energy per molecule is high, but the total energy transferred is small.
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
the same in each lamp
Ice tends to form at the
top surface of bodies of water.
If you plug an electric toaster rated at 110-V into a 220-V outlet, current in the toaster will be about
twice what it should be
The cooling effect inside a refrigerator is produced by
vaporizing the refrigeration liquid.
The electric power of a lamp that carries 2 A at 120 V is
240W
When 100 J of heat is added to a system that performs 60 J of work, the thermal energy change of the system is
40J
Four amps of current exist in the primary coil of a transformer. The voltage across the primary coil is 110 V. What is the power output of the secondary coil?
440 W
For ice to form on a pond, all the water in the pond must cool to
4°C
Increasing the temperature of 50 grams of water by 1°C requires
50 calories
A coulomb of charge that passes through a 6-V battery is given
6 joules
If you use 10 J of work to push a coulomb of charge into an electric field, its voltage with respect to its starting position is
10 V.
Which would burn the most?
100 g of steam at 100°C
Two charges separated by one meter exert a 1-N force on each other. If the charges are pushed to 0.25-m separation, the force on each charge will be
16 N
When mechanical work is done on a system, there can be an increase in its
Both thermal energy and temperature
Objects can absorb heat energy by
Convection, radiation, and conduction
Which statement is correct?
Current flows through a circuit.
We are able to completely convert all of a given amount of heat into mechanical energy.
False
Energy transfer is measured in units of
Joules and Calories
If a substance radiates more energy than it absorbs, its
Temperature and thermal energy decrease
An object will normally be a net radiator of energy when its thermal energy is
can't say, because thermal energy is not temperature
In an ac circuit, the electric field
changes magnitude and direction with time
Magnetic field lines about a current-carrying wire
circle the wire in closed loops.
If a volume of air is warmed, it expands. If a volume of air expands, it
cools
Ice is put in a cooler in order to cool the contents. To speed up the cooling process, the ice can be
crushed
An ampere is a unit of electrical
current
When air expands and no thermal energy is exchanged, the air temperature will
decrease
As a piece of metal with a hole in it cools, the diameter of the hole
decreases
Every proton in the universe is surrounded by its own
gravitational and electric field
If a compass is moved from the northern hemisphere to the southern hemisphere, its magnetic needle will change direction
hardly at all
The reason the Sun's radiant energy is of shorter wavelengths than the earth's is because the Sun
has a higher temperature than the earth.
Newton's law of cooling applies to objects that are
heating and cooling
Which of the following contracts most when the temperature is decreased? Equal volumes of
helium
As a system becomes more disordered, entropy
increases
At the same temperature, which move with the greater speed in the air?
very light molecules
An electric motor and electric generator are
very similar devices.
Evaporation is a cooling process and condensation is a
warming process.
Which will increase temperature fastest when heat is applied?
water
Which of the following expands most when the temperature is lowered? Equal volumes of
water at 4°C
To say that evaporation is a cooling process is to say that the
water left behind cools.
The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was
zero
If you use 10 J of work to push a charge into an electric field and then release the charge, as it flies past its starting position, its kinetic energy is
10J
When a pair of 1 ohm resistors are connected in series, their combined resistance is
2 ohms, and when in parallel, 1/2 ohm
When a 10-V battery is connected to a resistor, 2 A of current flow in the resistor. What is the resistor's value?
5 ohms
If you were caught in freezing weather with only a candle for heat, you would be warmer in
an igloo
As more lamps are put into a series circuit, the overall current in the power source
decreases
If glass expanded more than mercury, then the column of mercury in a mercury thermometer would rise when the temperature
decreases
The fundamental force underlying all chemical reactions is
electrical
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
fall closer together
Which of the following expands most when the temperature is increased? Equal volumes of
helium
The moderate temperatures of coastal areas is due to water's
high specific heat capacity.
Food in a pressure cooker is cooked faster because of the
higher temperature
Compared to the polar ice caps, a hot cup of coffee has
higher temperature, but less thermal energy.
In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of
hydrogen
If you run a refrigerator in a closed room with the refrigerator door open, the room temperature will
increase
Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will
increase
When air is compressed and no thermal energy is exchanged, the air temperature will
increase
When an iron ring is heated, the hole becomes
larger
As compared to the same mass of completely liquid water, slushy water tends to make it
less dense
When a light switch is turned on in a dc circuit, the average speed of electrons in the lamp is
less than 1 cm/s.
Sand which is hot during the day and cold at night is because it has
low specific heat capacity
A material that increases in temperature relatively quickly has a
low specific heat capacity.
To turn 50 g of boiling water to steam requires
more calories than is required to bring 50 g of ice at absolute zero to the boiling point.
Rub electrons from your hair with a comb and the comb becomes
negatively charged.
To say that electric charge is conserved means that no case has ever been found where
net charge has been created or destroyed
In an electrically neutral atom the number of protons in the nucleus is equal to the number of
neutrons in the nucleus.
To melt 50 g of 0°C ice requires
no calories
The current in a 100-W bulb connected to a 120-V source is
none of these
An inventor discovers a harmless and tasteless salt, which, when added to water changes its boiling point. The market value for this salt will be best if the salt
raises the boiling point of water.
If you heat a sealed container of air on a burner. The air will have an increase in
thermal energy, pressure, and temperature
A circuit is powered with a battery. Current flows
through both the battery and the rest of the circuit.
We are warmed by condensation because water molecules in the air that strike our bodies
transfer some of their kinetic energies to us.