Semester 2 study guide

A heater uses 21 A when connected to a 110-V line. If electric power costs 10 cents per kilowatt-hour in this location, the cost of running the heater for 13 hours is

$3.00

Cross-country power lines carry voltages of about

120,000 V

A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot as a temperature of about

273 degrees C

A 2-C charge and a 4-C charge attract each other with 10N of force. How much will a 2-C charge and a 12-C charge attract each other when place the same distance apart?

30 N

Two charges separated by a distance of 1 meter exert a 20-N force on each other. If the charges are pulled to a 2 meter separation distance, the force on each charge will be

5 N

An ideal polarizing filter will transmit 50% of nonpolarized light incident on it. How much light is transmitted by two ideal polarizing filters that are oriented with their axes parallel to each other?

50%

Where does a satellite in an elliptical orbit have the greatest kinetic energy?

At the point closest to the planet

True or false: Because Earth is "falling" around the sun, it will eventually crash into it.

False

True or false: Electrical forces are strong, but in comparison, gravitational forces are stronger

False

True or false: Gases don't expand very much when heated

False

True or false: Heat transfer by means of electrons colliding with other electrons in a mental is convection

False

True or false: In order for a seesaw to be in rotational equilibrium, the sum of torques acting on it need not be balanced if one person sits closer to the fulcrum than the other person

False

True or false: Magnetic domains are regions in a material where clusters of atoms are randomly magnetized

False

True or false: The distance between a turning axis and the point of contact of a perpendicular force is called the fulcrum

False

True or false: The energy stored in a capacitor comes from the work required to discharge it

False

True or false: The speed of a satellite in a circular orbit around Earth changes as it circles Earth

False

True or false: The unit of electric potential is the joule

False

True or false: The word "pitch" refers to the period of a sound wave

False

True or false: When you look at the image of a candle in a plane mirror, you see a real image

False

True or false: You are walking through a parking lot on a hot summer day. The air near the ground is slightly warmer than the air above, which means that sound waves from a distant car horn will refract toward the ground so that you will be able to hear the horn clearly

False

A 60-W light bulb and a 100-W light bulb are each connected to a 120-V outlet. Which light bulb has more current in it?

The 60-W bulb

True or False: Ladybugs on the inside of a spinning bicycle tire can experience a force that feels like gravity to them

True

True or false: It is possible for a rocket to leave the surface of Earth and travel to the moon without its speed ever reaching Earth's escape speed

True

True or false: There is a magnetic field around a current-carrying wire

True

True or false: when an object is forced to vibrate at its natural frequency, its vibration amplitude increases

True

True or false: when steam changes to water at 100 C , energy is released

True

the molecules in a room temperature glass of water jostle around at

a great variety of speeds

If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with a greater speed

a larger voltage is induced

If the north pole of one magnet is brought near the south pole of another magnet, the poles will

attract each other

The reason satellites orbit Earth at least 150 km above the surface is to

be above Earth's atmosphere

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

current is the same in each lamp

What expands most when the temperature is lowered? a. helium b. iron c. wood d. water at 4 degrees C

d.- water at 4 degrees C

Clouds form when warm air

expands, rises, and chills

torque is defined as

force times lever arm

Every proton in the universe is surrounded by its own

gravitational and electric field

Nellie swings a rock into a circular parth while holding an attached string overhead. The string makes a 45-degree angle to the vertical (compromising a "conical pendulum"). The centripetal force that holds the rock in its circualr path is the

horizontal component of the string tension

If you squeeze a balloon to one half its original size, the pressure inside

increases by a factor of 2

A rainbow nicely illustrates an example of light

internal reflection and refraction

Newton hypothesized that the moon

is a projectile, is falling around Earth, has tangential velocity that prevents it from falling into Earth, and is actually attracted to Earth

A magnet is moved in and out of a coil of wire connected to several lamps. If the number of coils is doubled

it is harder to move the magnet

at the health spa, Felix Flex finds that pulleys on the exercise machines are not circular, but are cams—oval-shaped pulleys

length of lever arms and forces required to produce a given torque

if you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weight

more

A device that transforms electrical energy to mechanical energy is a

motor

The charge of an electron is

negative

If you comb your hair and the comb becomes positively charged, your hair becomes

negatively charged

If you comb your hair and the comb becomes positively chraged, your hair becomes

negatively charged

If a compass is moved from the Northern Hemisphere to the Southern Hemisphere, its magnetic needle will change direction

not at all

A 1134-Hz tuning fork is sounded at the same time a piano note is struck. You hear three beats per second. What is the frequency of the piano string?

not enough info to solve

the colored dots that make up the color on a TV screen are

red,blue, and green

A projectile is fired vertically from the surface of Earth at 10 km/s. The projectile will

rise and then fall back to Earth's surface

Morning dew of the grass is a result of

slow-moving molecules condensing on the grass

Compared to its speed in air, the speed of light in water is

slower

Compared to the gravitation on the surface of earth, the gravitational field well below Earth's surface is

smaller

The circular orbit of a satellite orbiting Earth is characterized by a constant

speed, radius, and magnitude of acceleration

Which of the following is a device used to either cut off or allow electrons to flow in a circuit?

switch

the center of mass of a human body is located at a point

that changes as a person bends over

The law of reflection says that

the angle of reflection from a mirror equals the angle of incidence

Light shines on a pane of green glass and a pane of clear glass. The temperature will be higher in

the green glass

When a virtual image is created in a plane mirror

the image is located behind the mirror

Which has more lift, a heavy plane flying at a low speed or a light plane with wings the same size and shape flying at a high speed?

the light plane

To say that evaporation is a cooling process means that when evaporation occurs,

the remaining liquid cools

In physics lab, you hang a wire perpendicular to the magnetic field created by a horseshoe magnet. You observe that the wire moves downward when you allow current to flow through it. What happens when you reverse the direction of current?

the wire moves upward

Two parallel plates are oppositely charged. The left plate is negative and the right plate is positive. In which direction does the electric field point?

to the left

In a simple parallel circuit

voltage across each branch is always the same

A step-up transformer increases

voltage from primary to secondary

Cool a sample of air from zero on the Celsius scale to near zero on the absolute scale and the air loses

volume and pressure

As a high-altitude balloon sinks lower and lower into the atmosphere, its

volume decreases

Refraction occurs

when a wave changes speed

Suppose a hollow metal sphere has a large negative charge on it. The electric field strength inside the sphere is

zero