Physical Science Ch. 6 & 7

The musical note A has a frequency of 440 Hz and its wavelength in seawater is 3.5 m. The speed of sound in seawater is

1540 m/s.

A charge of +Q attracts a charge of -Q 1 cm away with a force of F. Another charge of +Q is placed next to the first one. The force on the charge of -Q is now

2F

A boat at anchor is rocked by waves whose crests are 50 m apart and whose speed is 10 m/s. These waves reach the boat once every

5 s.

The voltage needed to produce a current of 8 A in a resistance of 12 ohms is

96 V.

Interference in the waves is the ____ together of two or more waves of the same kind that pass by the same point and at the same time.

adding

Electromagnetic waves are

combined electrical and magnetic disturbacnes

An electric charge involves the gain or loss of ______ from an object; these particles do not leave the object until there is a discharge.

electrons

The ____ carried by an electromagnetic field is constantly being exchanged between its fluctuating electric and magnetic fields.

energy

Frequency

is the number of cycles per second

Protons and electrons have different masses. When they are the same distance apart, the electric force between two electrons

is the same as the force between two protons.

Relative to its object, a real image formed by a lens is always

larger

You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be

less than 1.2 m deep.

Shadows are not completely dark because _____

light waves are able to diffract around the object causing the shadow

Relative to the focal length of a wide-angle camera lens, the focal length of a telephoto lens is

longer

The more energy a sound wave carries, the _______ it will sound.

louder

The greater the decibel (dB) level of a sound wave, the

louder it is.

The amplitude of a sound wave determines its

loudness

The current with which a transformer is used

must be ac.

An eye with the defect of farsightedness has trouble bringing into focus objects that are, _____ and in nearsightedness, the eye has trouble bringing into focus _____ objects.

near, distant

A ground fault interpreter works by breaking the circuit faster than a fuse or circuit breaker can by ______.

noting a current difference between the load-carrying wire and the system ground wires

The ratio of 1 volt to 1 amp defines the unit of resistance called an ______.

ohm

Polarized light can be made by passing light through a material that _______.

only allows light aligned in a certain direction to pass

Doubling the rate of energy flow producing a particular sound will make the loudness of the sound produced _____.

only slightly louder

A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is

parallel to the field.

The number of seconds per cycle is called the wave's _____, and the number of cycles per second is the wave's _____

period, frequency

In an electromagnetic wave, the electric field is

perpendicular to both the magnetic field and the wave direction.

In a transverse wave, the individual particles of the medium move

perpendicular to the direction of travel.

Refracted light is light that has been bent from a straight path. Light that is turned sharply without being bent is called _____ light.

reflected

A lens is a piece of glass or other transparent material that can produce an image by ____ light that comes from an object.

refracting

The change in direction of a light ray when it passes from one substance into another (from water into air) is called ______.

refraction

A positive electric charge

repels other positive charges.

Dispersion is the term used to describe the

splitting of white light into its component colors in refraction.

A magnetic field does not interact with a

stationary electric charge.

Wavelength Period Speed

the distance between two identical point on adjacent waves the amount of time for a wave to repeat itself the rate of motion of the wave

Larger lenses are needed for higher magnification because the larger the lens ____

the less significance diffraction is

Wave crest Wave trough Amplitude

the maximum disturbance from the undisturbed position the maximum disturbance in the opposite direction from the rest position the maximum displacement from the rest position

When a rubber rod is stroked with a piece of fur,

the rod becomes negatively charged and the fur becomes positively charged.

The location where beams of light appear to come from behind a diverging lens is called a(n) ____ focal point because the light rays do not actually pass through that spot.

virtual

An example of a wave that is partly longitudinal and partly transverse is a

water wave.

Relative to the electric force between two protons, the gravitational force between them is

weaker.

Refraction of light ray occurs

when a light ray changes direction passing through the boundary between two materials

The watt, the unit of power, is equal to the

(volt)(ampere).

A 80-dB sound carries more energy than a 40-dB sound by a factor of

10,000

The standard home in the United States is wired with 120V. If a coffee maker draws a current of 10A, the resistance in it is _________ coulomb.

12 R=V/I, therefore, 120V/10A=12 coulombs.

Ocean waves with a period is 10 s are found to have a wavelength of 120 m. Their speed is

12 m/s.

Ocean waves whose period is 8 s are observed to have a wavelength of 100 m. Their speed is

12.5 m/s.

The speed of light in a transparent plastic whose index of refraction is 1.5 is

2 × 108 m/s.

Two 240-watt light bulbs are connected in parallel across a 120-V power line. The current in each bulb is

2.0 A.

The primary coil of a transformer has 200 turns and its secondary coil has 50 turns, and the current in the secondary coil is 40 A. When a 12-V alternating current is applied to the primary coil of the transformer, the secondary voltage will be

3 V.

Radio amateurs are permitted to communicate on the "10-meter band". What frequency of radio waves corresponds to a wavelength of 10 meters? The speed of radio waves is 3 × 108 m/s.

3.0 × 107 Hz

A medal in a plastic cube whose index of refraction is 1.5 appears to be 20 mm below the upper surface of the cube. The depth of the medal is actually

30mm.

The primary coil of a transformer has 200 turns and its secondary coil has 40 turns. If the current in the secondary coil is 25 A, the current in the primary coil is

5 A.

The ratio of the speed of light in a vacuum to the speed of light in a material is called the

Index of refraction Mathematically n=c/v

Electric neutrality of an object occurs where there is _____.

a balance of negative and positive charges

Longitudinal waves cause vibrations to occur in ______.

a direction parallel to their own environment

Relative to the radio signals sent out by a spacecraft headed away from the earth, the signals that are received on the earth have

a lower frequency.

A changing electric field gives rise to

a magnetic field

White light is best described as _____

a mixture of many colors

If two waves meet, the sum of the two separate _____ determines the resulting wave's amplitude.

amplitudes

When we look into a mirror, we appear to be behind the surface of the mirror. This is because light ______.

appears to travel in a straight line whereas it is really being reflected off the surface of the mirror

Newton's law of gravity and Coulumb's law are both fundamental laws and resemble each other in equation form. However, a major difference is gravitational forces _______.

are always attractive, but electric forces can be attractive or repulsive

The sky appears to be blue because

blue wavelengths are the most easily scattered in the atmosphere

Longitudinal waves create pulses of jammed-together molecules called ______ and alternatively pulses of thinned-out molecules called ______.

compressions; rarerarefractions

specialize in color vision specialized for low light conditions but cannot detect color

cones rods

Energy is carried in an electromagnetic wave by ______.

constantly being exchanged between the fluctuating electric and magnetic fields

A lens that brings parallel beams of light into single focal point is called a ____ lens.

converging

The image shows the path of light in the eye of a person who is farsighted. The light can be made to focus on the retina by using a ____ to ____ the light rays before they enter the eye.

converging lens; coverage

The blank scale ____ is used to describe the power of sound.

decibel

The ability of all waves to bend around the edge of an obstacle in their path is called _____

diffraction

The bending of waves around the edge of an obstacle in their path is an example of

diffraction.

A(n) _____ charge is produced whenever there is an imbalance between positive and negative charges.

electric

The excess number of electrons multiplied by the charge of one electron gives the ______.

electric charge

The conventional unit of battery capacity is the ampere-hour, which is actually a unit of

electric charge.

The particle easiest to remove from an atom is an

electron.

The greater the amplitude of a wave, the greater its

energy.

An eyeball that is too short will cause light from nearby objects to come into focus behind the retina (out of focus on the retina). This condition is known as ____

farsightedness

A converging lens of focal length f produces a real image of a real object when the object is

farther than f from the lens.

An electric field is subjected to a magnetic field that is parallel to it. As a result of the interaction, the electric field will ______.

feel nothing

The distance from a converging lens to the point where all the light rays come together is called the ____ of the lens.

focal length

The two magnetic poles of a magnet are where the _______.

forces of attraction seem concentrated

Overtones occur at those _____ that produce standing waves in a string attached at both ends.

frequencies

The property of light waves that leads to the phenomenon of color is

frequency

When a sound wave goes from air into water, the quantity that remains unchanged is its

frequency

A sound wave whose frequency is 50 Hz

has a relatively long wavelength.

Superconductors

have no electrical resistance.

Amplitude

is the largest displacement from the equilibrium position

Period

is the number of seconds per cycle

Maglev trains are trains that use _______.

magnetic forces to "levitate" the trains to eliminate friction

No matter how many times you cut a magnet in half, each piece will itself have a north and South Pole. This line of evidence supports the idea that ______.

magnetism is property of individual atoms

If a bar of iron is magnetized, the overall magnetic field is the result of ________.

many or all the iron atoms aligning

At different places on the earth's surface, the earth's magnetic field

may be different in both magnitude and direction.

Wavelengths are measured in

meters

Traveling at the speed of light in space, the electric and magnetic fields of an electromagnetic wave are _____ to each other and _____ to the direction of travel of the wave.

perpendicular, perpendicular

Which one of the following effects does not occur in all types of wave?

polarization

A simple way to find the properties of the image formed by a lens is to do

ray tracing

The image the lens of the eye forms on the retina is

real and inverted.

Light of which of the following colors has the longest wavelength?

red

An atom consists of a

small positive nucleus surrounded at a distance by electrons.

An example of a purely longitudinal wave is a

sound wave.

Of the following kinds of waves, the ones that cannot travel through a vacuum are

sound waves.

An electric current contains some device in which work is done (a lamp, for example) and therefore must contain a device that gives the _______.

source of energy to move the charges

Sound waves of frequency 300 Hz have a speed relative to sound waves in the same medium of frequency 600 Hz that is

the same

Two charges of +Q are 1 cm apart. If one of the charges is replaced by a charge of -Q, the magnitude of the force between them is

the same.

Dispersion of light means

the separation of light into different colors sorted by wavelengths

Cornea Retina Optic Nerve Ciliary muscle

the transparent outer membrane the light-sensitive part that converts when is seen into nerve impulses carries impulses to the brain changes the shape and focal length of the lens to focus on objects at different distances

Sound waves whose frequency is 300 Hz have a wavelength relative to sound waves in the same medium whose frequency is 900 Hz that is

three times as great.

Direct electric current cannot be used to operate

transformers.

Mechanical Waves

traveling vibrations in a medium

Sound waves of frequency 300 Hz have a wavelength relative to sound waves in the same medium of frequency 600 Hz that is

twice as great

Sonar (both medial and nautical) uses sounds with frequencies in the _____ range.

ultrasound

Sound waves with frequencies greater than 20,000 Hz are known as _____, whereas though with frequencies of less than 20Hz are known as _____.

ultrasound, infrasound

Curved mirrors, such are those used to look around blind corners, produce a ____ image.

virtual

A frequency that is not an overtone of the fundamental frequency F is

F/2