Physical Science - Exam #3

अब Quizwiz के साथ अपने होमवर्क और परीक्षाओं को एस करें!

Why does the north pole of a magnet point to the Earth's magnetic north pole if like poles repel? Check all that apply.

-The geographic North Pole is a magnetic south pole. -The north pole of a magnet is named after "north seeking," so a north pole points north.

An electrostatic charge, commonly called static electricity, can be produced

-by transferring electrons through friction -by transferring electrons direct contact between the objects -by induction which redistributed electrons through a material

When a switch is closed in a DC electrical circuit,

-electrons flow through the conductor at a very slow speed. -the electric field moves through the conductor at nearly the speed of light. -the current flow is proportional to the potential difference.

Electrical charge

-is measure in units of coulombs -of an electron is 1.60 x 10^-19 coulombs -of an electron cannot be divided -of 1 coulomb equals the charge of 6.24 x 10^18 protons

One theory as to the cause of Earth's magnetic field is

. the flowing of liquid iron and nickel within the core as Earth rotates.

In an ideal transformer, the primary voltage is 120 V and the primary current is 2.0A. If the output voltage is 1200 V, the output current will be

0.2 A

The potential difference that is created by doing 1.00 joule of work in moving 1.00 coulomb of charge is defined to be

1.0 volt

What is the current in a 67.9 Ω resistor when the potential difference across it is 120.0 V ?

1.76

An electric current through a wire is 8.28 C every 4.26 s . What is the magnitude of this current?

1.94

A typical air conditioner unit draws a current of 25 A with a voltage of 220V. If the air conditioner "runs" for 240 hours a month, what does it cost to run if the cost of 1 kWh is $0.10.

132$

Which numbered arrow is the refracted ray indicated by?

2

The speed of light is 3.00 x 108 m/s. If the index of refraction of glass is 1.50, The speed of light in glass is

2.00 x 10^8 m/s.

The frequency of a photon of red light that has a wavelength of 680 nm is

2.27 x 10-15 Hz.

Consider an electrical transformer has 10 loops on its primary coil and 20 loops on its secondary coil. What is the current in the secondary if the current is the primary coil is 5.0 A?

2.5 A

Consider an electrical transformer has 10 loops on its primary coil and 20 loops on its secondary coil. What is the voltage in the secondary coil if the primary coil is supplied with 120 V?

240 V

There is a current of 4.30 A through a toaster connected to a 120.0 V circuit. What is the resistance of the toaster?

27.9

If angle A is 60º, what does angle C measure?

30º

If a potential difference of 12.0 V is required to produce a current of 3.0 A in a wire, the resistance of the wire is

4.0 Ohm (Ω)

A ray of orange light has a frequency of 4.9 x 1014 Hz. The corresponding wavelength of this light is

612 nm

Can you name everyday things that make life easier for us because of electromagnets?

A. Electric meters B. Thermostats C. Mechanical switches on VCRs and doorbells D. Electric motors

What is the photoelectric effect?

A. Electrons are emitted when specific materials are exposed to light. B. Energy of a light wave occurs in discrete amounts of energy called quanta. C. Einstein defined the quanta as photons. D. Light is a stream of moving particles called photons

When viewed from a stationary platform, an object moving at speeds approaching the speed of light would, according to the Special Theory of Relativity,

A. be shorter than when it was not moving. B. have an increased mass. C. find that time has slowed down.

Light that interacts with matter can be

A. reflected. B. absorbed. C. transmitted

Which of the following are misconceptions concerning electric current?

AThe electrons move at nearly the speed of light through a wire. B. Electrons are pushed out of the wire as more enter the wire. C. The flow of electrons is like the flow of water in a pipe.

If 1 is the incident ray, what is the angle of reflection?

B

The unit of electric charge is called a(n)

Coulomb

How does an electric generator generate an electric current? The generator

Does work in moving electrons, which creates an electric field.

A common fundamental property of both electrons and protons is

Electric Charge

In an experiment in the late 1800's, J. J. Thomson discovered that all matter contained negatively charged particles. These particles were named after the Greek word for amber. Today these sub-atomic particles are named

Electrons

What causes an electron to move toward one end of a wire when the wire is moved across a magnetic field?

Electrons have magnetic fields that interact with an external magnetic field.

Electrons move from the power plant to homes in an alternating current.

False

If one cuts a current carrying wire, the flow of electricity will spill out into the air.

False

Interference is a property of light most easily explained by the particle model

False

Longer wavelengths are affected more by a prism or water droplets than are the shorter wavelengths.

False

The electrical force is much weaker than the force of gravity.

False

The sky appears blue due to the light reflected from the oceans.

False

A transformer in which the number of turns in the primary coil is greater than the number of turns in the secondary coil

Is called a step down transformer.

Is a kWh a unit of power or a unit of work?

It is a unit of work since W=Pt (from P=W/t)

What are the units of h in the equation E = hf?

Jxs

What property of light do you have to keep in mind while looking at fish in a lake or stream?

Light bends when it hits the air to water interface. The fish that you spotted is not where you think it is.

How is an unmagnetized piece of iron different from the same piece of iron when it is magnetized?

Magnetic domains are randomly oriented in unmagnetized iron, aligned in magnetized iron.

Which of the following is not luminous?

Moon

The frequency of light is

None of the answers is correct

Which of the following properties of light cannot be described by using the wave model of light?

Photoelectric effect

A conductor is a material which has electrons that are free to move. Which of the following is a conductor?

Silver Spoon

The operation of the household circuit breaker depends on what property of an electrical current?

The electrical current produces a magnetic field which opens the circuit breaker.

Why do polarized sunglasses reduce glare (reflected light)?

The reflected light is polarized in the horizontal plane and the glasses are polarized in the vertical plane.

The magnitude of an induced voltage does NOT depend on

The resistance of the wire.

Why is the sky blue?

The shorter wavelengths of blue and violet light are scattered more strongly than red and orange light.

Charge moving through a wire produces a magnetic field around the wire.

True

Glare is light that tends to be polarized predominantly in the horizontal plane.

True

If you double the distance between two charged objects, you reduce the electrical force by a factor of four.

True

The attractive force between two unlike charges has the same strength as the repulsive force between two like charges.

True

The north end of a suspended magnet will point to Earth's magnetic north pole.

True

The range of energies emitted by the Sun is most intense near the yellow-green wavelengths.

True

The slower light through a given substance, the greater the index of refraction.

True

The volt is a measure of the difference in electrical potential energy between two points.

True

Ultraviolet light waves carry more energy than infrared light waves.

True

A lightbulb with a resistance of 14.5 Ω allows a 0.73 A current to flow when connected to a battery.

Voltage: 10.58 Power: 7.72

Electric power is measured in units of

Watts

Which of the following has the highest energy (i.e. highest frequency)?

X-ray

The reason that someone can see a reflection in a mirror is that

a mirror is a smooth surface and light rays reflect from the surface of the mirror are parallel to each other in a definite direction.

What is a magnetic pole?

a side where the magnetic force seems to be concentrated

What is a magnetic pole?

a side where the magnetic force seems to be concentrated

Polarizing sunglasses are useful because they are able to

absorb reflected light, which is polarized.

An electric current is measured in units of

amp

Which of the following unit is actually a measure of a rate?

amp

The rate of flow of electric charge is measured in

amperes

What is it that travels through an electric circuit at near the speed of light?

an electrical field

Max Planck discovered that the blackbody radiation emitted by vibrating molecules

appeared to come in multiples of certain fixed amounts.

Which of the following is an incandescent light source?

candle

Near-sightedness, or myopia, can be corrected with which type lens?

concave

The incident angle of a light ray that travels from water to air and is refracted at 90o is called the

critical angle

The flow of charge is defined as

current

Electric power is

current times voltage

When white light is passed through a prism at the correct angle, the colors of the rainbow are produced. This dispersion of light is due to the fact that

each color of light has its own index of refraction.

When an electric stove element is hot enough, it gives off a dull red glow. When it cools to the point that it no longer glows, it will

emit only longer wavelength energy.

An electric current is a(an)

flow of charge

In 1820, Hans Oersted discovered that electrical currents produce magnetic fields when

he found that a wire carrying a current deflected the needle of a magnetic compass.

A rainbow always appears

in the part of the sky opposite from the Sun.

The majority of the Sun's radiant energy is in the form of

infrared radiation

An electric field

is always present around an electron.

The ratio of the speed of light in a vacuum to the speed of light in a medium

is called the index of refraction

The force between two charged particles

is inversely proportional to the distance between them squared.

The natural magnetic field surrounding Earth

is produced by moving charges in Earth's core.

The north pole of a magnet is so named because

it points to the earth's north magnetic pole.

The Sun appears reddish as it sets because

more of the shorter, bluer wavelengths are scattered away by the dust and haze.

Our eyes are most sensitive to sunlight with a frequency that is

near the yellow-green region of the visible spectrum.

A neutrally charged atom that gains one or more electrons is called a(n)

negative ion

If you were to mechanically rotate the armature in an electric motor

nothing would happen

Electrical resistance is a property of conductors that is measured in units of

ohm

Polarized light vibrates

only in one plane

If you multiply amp Χ ohm, the answers will be in units of

potential

A blue SUV appears blue because it

reflects blue light in the 460 nm to 490 nm range.

A mirage is caused by hot air near the ground

refracting light rays upward.

Ohm's law states

that the current in a circuit increases if the potential difference increases.

The photoelectric effect could not be adequately explained with a wave model of light because

the energy of the ejected electrons did not depend upon the intensity.

The index of refraction for flint glass is 1.5. This means that

the speed of light is slower in this substance than it is in vacuum.

Electric field lines are drawn

to show the direction a test charge would move

Phenomena such as diffraction and interference can be most easily explained in terms of the

wave model of light


संबंधित स्टडी सेट्स

Unit 1: Intro to Anatomy & Physiology

View Set