Physical Science Test 3

*Ocean waves whose period is 8 s are observed to have a wavelength of 100 m. Their speed is A. 0.25 m/s. B. 12.5 m/s. C. 25 m/s. D. 400 m/s.

12.5 m/s

True or False A person suffering from nearsightedness can see distant objects clearly, but cannot focus on nearby objects.

False. A nearsighted person can see nearby objects clearly but has difficulty focusing on distant objects.

True or False Cutting a magnet in half results in one-half having a single north pole and no south pole, and the other half having a single south pole and no north pole

False. Each half has both a north pole and a south pole; magnetic poles always come in pairs.

True or False Hearing the noise of a car horn around the corner of a building is an example of reflection.

False. Hearing the noise of a car horn around the corner of a building is an example of diffraction.

True or False Ohm's law applies to metallic and liquid conductors, but not to gaseous conductors

False. Ohm's law applies only to metallic conductors and not to gaseous or liquid conductors.

True or False Sound waves travel faster in air than in liquids or solids.

False. Sound waves travel faster in liquids and solids.

True or False The electrons in a metallic conductor carry the current

False. The electrons in a metallic conductor do not carry the current; the moving electrons are the current

True or False The force a magnetic field exerts on an electric current disappears when the current is perpendicular to the magnetic field

False. The force a magnetic field exerts on an electric current is perpendicular to the magnetic field.

True or False Rubbing a glass rod with silk creates positive electric charges within the glass rod, giving it an overall positive charge

False. The glass rod, prior to rubbing with silk, was electrically neutral, meaning it had equal amounts of positive and negative charges. Rubbing with silk removed some of the rod's negative charges (electrons), giving the rod an overall positive charge

True or False Heating or hammering a magnet destroys the magnetic fields of its atoms or molecules

False. The magnetic properties of the magnet's atoms or molecules are not destroyed by heating or hammering the magnet. Instead, the atoms and molecules become randomly arranged, which cancels out their collective magnetic effect.

True or False In a transverse wave, the particles of the medium move parallel to the wave direction.

False. The particles move perpendicular to the wave direction in a transverse wave.

True or False The smaller the f-number of a camera lens, the smaller the lens opening

False. The smaller the f-number, the larger the lens opening

True or False A stationary electric charge has no magnetic properties

True

True or False Electric energy is useful partly because it is easily transformed into other kinds of energy

True

True or False Electromagnetic waves differ from mechanical waves in their ability to travel through a vacuum as well as matter.

True

True or False In 1864, James Clerk Maxwell proposed that an accelerated electric charge generates combined electrical and magnetic disturbances called electromagnetic waves.

True

True or False In a transformer, the electrical power is the same in both coils independent of the number of turns in each coil

True

True or False The force between two charged objects depends upon the distance between the objects and the magnitude of each charge

True

True or False The size and shape of a musical instrument is largely responsible for its natural frequencies of vibration or resonance.

True

True or False The speed of light in a medium such as air or glass is slightly different for different frequencies.

True

True or False The sun appears a brilliant red at sunset because the atmospheric molecules and dust particles scatter the blue light more than the red.

True

*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: a. 3 V b. 6 V c. 48 V d. 24 V

a. 3 V

Radio waves and X-rays are examples of a. electromagnetic waves b. mechanical waves c. pressure waves d. longitudinal waves

a. electromagnetic waves

When the rubber rod is stroked against the piece of fur a. electrons are transferred from the fur to the rubber rod b. electrons are transferred from the rubber rod to the fur c. the fur becomes negatively charged d. the rubber rod becomes magnetized

a. electrons are transferred from the fur to the rubber rod

*You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be: a. less than 1.2 m deep b. 1.2 m deep c. any of the choices, depending on the height of the sun. d. more than 1.2 m deep.

a. less than 1.2 m deep

*At different places on the earth's surface, the earth's magnetic field: a. may be different in both magnitude and direction b. may be different in magnitude but not in direction c. may be different in direction but not in magnitude d. is the same in direction and magnitude

a. may be different in both magnitude and direction

Ohm's law holds only for a. metallic conductors b. gaseous conductors c. liquid conductors d. transistors

a. metallic conductors

*A molecule that has lost an electron becomes a A. positive ion B. negative ion C. nucleus D. superconductor.

a. positive ion

*A positive electric charge: a. repels other positive charges b. consists of an excess of electrons c. does not interact with other positive charges but only with negative ones d. attracts other positive charges

a. repels other positive charges

When the plastic ball is touched by the rubber rod a. some of the charge is transferred from the rubber rod to the plastic ball b. charge flows from the plastic ball to the rubber rod c. the charge in the rubber rod is neutralized d. no charge is transferred between the rubber rod and plastic ball

a. some of the charge is transferred from the rubber rod to the plastic ball

*Of the following kinds of waves, the ones that cannot travel through a vacuum are: a. sound waves b. X-rays c. radio waves d. light waves

a. sound waves

Which one of the following waves cannot travel through a vacuum? a. sound waves b. radio waves c. light waves d. X-rays

a. sound waves

*A magnetic field does not interact with a A. stationary electric charge B. moving electric charge C. stationary magnet D. a moving magnet.

a. stationary electric charge

*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: a. the same b. zero c. larger d. smaller

a. the same

*Protons and electrons have different masses. When they are the same distance apart, the electric force between two electrons a. the same as the force between two protons b. less than the force between two protons c. any of the choices, depending on the distance between each pair of particles d. is greater than the force between two protons

a. the same as the force between two protons

*Sound waves whose frequency is 300 Hz have a wavelength relative to sound waves in the same medium whose frequency is 150 Hz that is A. twice as great. B. the same. C. half as great. D. 4.5 times as great.

a. twice as great

*Relative to the electric force between two protons, the gravitational force between them is: a. weaker b. equal in magnitude c. any of the choices, depending on how far apart the protons are d. stronger

a. weaker

*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: a. 3 × 108 m/s b. 1540 m/s c. 126 m/s d. 80 m/s

b. 1540 m/s

Two waves having the same frequency and equal amplitude A meet exactly in step at the same point. The resulting amplitude is a. 0.5 b. 2 A c. unchanged d. zero

b. 2 A

Human ears are most sensitive to sounds whose frequencies are between a. 10,000 and 20,000 Hz b. 3000 and 4000 Hz c. 5000 and 8000 Hz d. 20 and 1500 Hz

b. 3000 and 4000 Hz

*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: a. 2.5 A b. 5 A c. 6.4 A d. 125 A

b. 5 A

*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. a lower speed. B. a lower frequency. C. a shorter wavelength. D. All the properties listed.

b. a lower frequency

Oersted's experiment demonstrated that a. a compass needle points toward the earth's north magnetic pole b. a magnetic field surrounds every electric current c. field lines surround every magnet d. an electric charge at rest has magnetic properties

b. a magnetic field surrounds every electric current

A narrow beam of white light is passed through a prism and is separated into beams of light of various colors. This is an example of a. interference b. dispersion c. total internal reflection d. resonance

b. dispersion

The ampere is the unit of a. resistance b. electric current c. potential difference d. charge

b. electric current

*The greater the amplitude of a wave, the greater its: a. frequency b. energy c. wavelength d. speed

b. energy

*A compass needle tends to A. line up perpendicular to a magnetic field B. line up parallel to a magnetic field C. turn slowly in a constant magnetic field D. point only toward the North Pole.

b. line up parallel to a magnetic field

*A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is: a. perpendicular to the field b. parallel to the field c. either parallel or perpendicular, depending on the direction of the current d. at a 45-degree angle with the field

b. parallel to the field

*The watt, the unit of power, is equal to the: a. (volt)(ohm) b. volt/ampere c. (volt)(ampere) d. ampere/volt

c. (volt)(ampere)

*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: a. F/2 b. F c. 2F d. 4F

c. 2F

If you divide voltage by resistance, the answer will be in units of a. coulombs b. ohms c. amperes d. watts

c. amperes

Which one of the following wave quantities is not related to the others? a. speed b. frequency c. amplitude d. wavelength

c. amplitude

*The bending of waves around the edge of an obstacle in their path is an example of: a. reflection b. refraction c. diffraction d. the Doppler effect

c. diffraction

*The conventional unit of battery capacity is the ampere-hour, which is actually a unit of: a. energy b. potential difference c. electric charge d. power

c. electric charge

*Superconductors: a. have no practical applications b. are used in making transistors c. have no electrical resistance d. have very little electrical resistance

c. have no electrical resistance

*The greater the decibel (dB) level of a sound wave, the A. higher its frequency is. B. longer its wavelength is. C. louder it is. D. farther away its source is.

c. louder it is

A violin string is bowed and at the same time is touched lightly in the middle, causing the string to vibrate in two sections. The two vibrating sections produce sound frequencies called a. fundamental tones b. undertones c. overtones d. supertones

c. overtones

*In an electromagnetic wave, the electric field is: a. parallel to the magnetic field and perpendicular to the wave direction b. perpendicular to the magnetic field and parallel to the wave direction c. perpendicular to both the magnetic field and the wave direction d. parallel to both the magnetic field and the wave direction.

c. perpendicular to both the magnetic field and parallel to the wave direction

*In a transverse wave, the individual particles of the medium move: a. in circles b. parallel to the direction of travel c. perpendicular to the direction of travel d. in ellipses

c. perpendicular to the direction of travel

A _____ circuit results when the connecting wires of an electric circuit accidently touch each other or are joined by a stray conductor a. live b. random c. short d. hot

c. short

The plastic ball flies away from the rubber rod because a. its electric field has been neutralized b. it has acquired an electric charge opposite that of the rubber rod c. some of the charge flows from the rod to the plastic ball and like charges repel d. the rod's magnetic field pushes the plastic ball away

c. some of the charge flows from the rod to the plastic ball and like charges repel

*An example of a purely longitudinal wave is a: a. light wave b. water wave c. sound wave d. wave in a stretched string

c. sound wave

*A magnetic field does not interact with a: a. moving electric charge b. a moving magnet c. stationary electric charge d. stationary magnet

c. stationary electric charge

*When a rubber rod is stroked with a piece of fur: a. both the rod and fur become negatively charged b. any of the choices, depending on how hard the rod is stroked c. the rod becomes negatively charged and the fur becomes positively charged d. the rod becomes negatively charged while the fur remains neutral

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

*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: a. one-third as great b. the same c. three times as great d. nine times as great

c. three times as great

*Direct electric current cannot be used to operate: a. electric heaters b. electromagnets c. transformers d. electric motors

c. transformers

*An example of a wave that is partly longitudinal and partly transverse is a: a. sound wave b. wave in a stretched string c. water wave d. light wave

c. water wave

Define refraction

change in a wave's direction as it enters a different medium

Define reflection

change in a wave's direction when it strikes an obstacle

Fill in the blank In a simple direct-current electric motor, the ____________________ reverses the current periodically

commutator

Fill in the blank A(n)____________________ is a substance through which electric charge can flow.

conductor

Fill in the blank The ____________________ is the basic unit of electric charge.

coulomb

Fill in the blank A flow of charge from one place to another is an electric ____________________.

current

*An 80-dB sound relative to a 40-dB sound is more intense by a factor of A. 4. B. 40. C. 4000. D. 10000.

d. 10,000

*Ocean waves whose period is 8 s are observed to have a wavelength of 100 m. Their speed is: a. 800 m/s b. 100 m/s c. 0.08 m/s d. 12.5 m/s

d. 12.5 m/s

*Two 240-watt light bulbs are connected in parallel across a 120-V power line. The current in each bulb is: a. 0.5 A b. 1.0 A c. 4.0 A d. 2.0 A

d. 2.0 A

*The voltage needed to produce a current of 8 A in a resistance of 12 ohms is: a. 1.5 V b. 0.67 V c. 4 V d. 96 V

d. 96 V

*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. all the properties listed b. a lower speed c. a shorter wavelength d. a lower frequency

d. a lower frequency

*The primary coil of a transformer is connected to a source of direct current of voltage V. The voltage of the secondary current is A. zero B. equal to V C. higher than V D. Any of the choices, depending on the ratio of turns in the transformer coils.

d. any of these choices

*The particle easiest to remove from an atom is an: a. neutron b. proton c. nucleus d. electron

d. electron

*The property of light waves that leads to the phenomenon of color is A. speed. B. amplitude. C. acceleration. D. frequency.

d. frequency

*A sound wave whose frequency is 50 Hz: a. is very loud b. has a relatively short wavelength c. is very soft d. has a relatively long wavelength

d. has a relatively long wavelength

A stationary observer hears the whistle of an approaching train. To the observer, the frequency of the sound produced by the whistle appears to be a. lowest before the train reaches the observer b. lowest just as the train passes the observer c. the same before the train reaches the observer as after the train passes the observer d. higher before the train reaches the observer and lower after the train passes the observer

d. higher before the train reaches the observes as after the train passes the observer

*The current with which a transformer is used: a. must be bc b. may be neither dc nor ac c. may be either dc or ac d. must be ac

d. must be ac

The elementary particle that has no electric charge is the a. proton b. electron c. atomic nucleus d. neutron

d. neutron

The portion of the eye that contains the light-sensitive receptors is the a. lens b. cornea c. pupil d. retina

d. retina

*An atom consists of a: a. small negative nucleus surrounded at a distance by protons b. uniform distribution of positive charge in which electrons are embedded c. uniform distribution of negative charge in which electrons are embedded d. small positive nucleus surrounded at a distance by electrons

d. small positive nucleus surrounded at a distance by electrons

*Of the following kinds of waves, the ones that cannot travel through a vacuum are A. X-rays. B. radio waves. C. light waves. D. sound waves.

d. sound waves

The unit of electric power is the a. volt b. ohm c. ampere d. watt

d. watt

Define Benjamin Franklin

described charges as either positive or negative

Define Christian Oersted

discovered that every electric current generates a magnetic field

Define Kamerlingh Onnes

discovered the phenomenon called superconductivity

Define Michael Faraday

discovered the principle of the generator

Define wavelength

distance between adjacent wave crests or troughs

Fill in the blank An electrically neutral atom has equal numbers of protons and _____________________.

electrons

Fill in the blank ____________________ are elementary particles found in atoms and have a negative electrical charge.

electrons

Define wave speed

equal to wavelength times frequency

Define Alex Muller and George Bednorz

first to discover a material superconducting above 23 K

Fill in the blank A(n) ____________________ or circuit breaker interrupts a power line whenever an unsafe amount of current passes through it.

fuse

Fill in the blank ____________________ is the method of removing the charge from an object.

grounding

Fill in the blank When electric currents are transmitted, some of the electrical energy is lost as ____________________.

heat

Fill in the blank In a(n) ____________________, charge can flow only with great difficulty.

insulator

Fill in the blank ____________________ are atoms or molecules that have lost or gained one or more electrons.

ions

Define Thales of Miletus

made the first recorded studies of electricity

Fill in the blank Neutrons and protons are found in the ____________________ of an atom.

nucleus

Fill in the blank The unit of electrical resistance is the ____________________.

ohm

Fill in the blank The ____________________ of an electric current is the rate at which it does work.

power

Fill in the blank ____________________ is the property of a conductor that opposes the flow of charge passing through it.

resistance

Define dispersion

separation of white light into its individual colors or frequencies

Fill in the blank When the resistors in an electric circuit are joined end-to-end with the same current flowing through all of them, the resistors are in ____________________; when the resistors are arranged so that the total current is split among them, they are in ____________________.

series, parallel

Define Charles Coulomb

showed how the force between charges varied with their distance apart and the magnitude of each charge

Define ultrasound

sound frequencies above 20,000 Hz

Define infrasound

sound frequencies below 20 Hz

Fill in the blank ____________________ is the loss of all electrical resistance by certain materials at extremely low temperatures.

superconductivity

Define Andre Ampere

the unit of electric current is named for him

Define Alessandro Volta

the unit of potential difference is named for him

Define Georg Ohm

the unit of resistance is named for him

Define period

time needed for a wave to pass a given point

Define hertz

unit of frequency

Define decibel

unit of sound intensity

Fill in the blank The ____________________ is the unit of potential difference.

volt

Fill in the blank Electric power is the product of current and ____________________.

voltage

Fill in the blank The ____________________ , or potential difference, between two points is the work needed to take a charge of 1 C from one of the points to the other.

voltage