Science And Inventions

Front 1

Strip electrons from an atom and the atom becomes

Back 1

positive ion

Front 2

To say that electric charge is conserved means that no case has ever been found where the

Back 2

net charge has been created or destroyed

Front 3

A conductor differs from an insulator in that a conductor

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who knows

Front 4

Charge carriers in a metal are electrons rather than protons because electrons are

Back 4

loosely bound

Front 5

Electrons are made to flow in a wire when there is

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a potential difference across its ends

Front 6

A wire that carries an electric current

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may be electrically charged

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Charge flows in a

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closed circuit

Front 8

A wire carrying a current is normally charged

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not at all

Front 9

The primary source of electrons in an ordinary electrical circuit is

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the electrical circuit itself

Front 10

Alternating current is normally produced by a

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generator

Front 11

In a simple circuit containing a bulb, energy is given to the moving charges by

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a generator

Front 12

A positive ion has more

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protons than electrons

Front 13

Moving electric charges will interact with

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an electric field or a magnetic field

Front 14

Like kinds of magnetic poles repel while unlike kinds of magnetic poles

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attract

Front 15

An iron nail is more strongly attracted to the

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north or south pole - no difference

Front 16

Magnetic field lines about a current-carrying wire

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circle the wire in closed loops

Front 17

If we think of the Earth as a magnet, its north (-seeking) pole is nearest

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Australia

Front 18

Which pole of a compass needle points to a south pole of a magnet?

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north pole

Front 19

Outside a magnet, magnetic field lines are conventionally drawn from

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north to south

Front 20

When a bar magnet is broken in two, each half is

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as magnetic as the original magnet

Front 21

Thrust a magnet into a coil of wire and the coil

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has a current in it

Front 22

In an electrically neutral atom the number of protons in the nucleus is equal to the number of

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electrons that surround the nucleus

Front 23

To say that electric charge is quantized is to say that the charge on an object

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is a whole-number multiple of the charge of one electron

Front 24

To say that electric charge is conserved is to say that electric charge

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can neither be created nor destroyed

Front 25

Rub electrons from your hair with a comb and the comb becomes

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negatively charged

Front 26

An electron and a proton

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attract each other

Front 27

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

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negatively charged

Front 28

A balloon will stick to a wooden wall if the balloon is charged

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either positively or negatively

Front 29

The magnetic field strength inside a current-carrying coil will be greater if the coil encloses a

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rod of iron

Front 30

A device that transforms electrical energy to mechanical energy is a

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motor

Front 31

When a bar magnet is thrust into a coil of copper wire, the coil tends to

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repel the magnet as it enters

Front 32

A device that transforms mechanical energy into electrical energy is a

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a generator

Front 33

Electromagnetic induction occurs in a coil when there is a change in

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magnetic field intensity in the coil

Front 34

When Rutherford had a stream of alpha particles hit a gold foil, most of the particles

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went almost straight through

Front 35

X-rays are similar to

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gamma rays

Front 36

Which radiation has no electric charge associated with it?

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gamma rays

Front 37

Both X-rays and gamma rays are emitted from

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different parts of the atom

Front 38

The sources of Xrays and gamma rays, respectively, are

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electron clouds and the atomic nucleus

Front 39

A nucleon is either

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a proton or a neutron

Front 40

Once an alpha particle is outside the nucleus it is

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electrostatically repelled

Front 41

An atom with an imbalance of electrons to protons is

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an ion

Front 42

Deuterium and tritium are both

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forms of hydrogen and isotopes of the same element

Front 43

The atomic number of an element is the same as the number of its

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protons

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Different isotopes of an element have different numbers of

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neutrons

Front 45

Most alpha particles fired at a gold foil passthrough undeflected because the

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atoms of gold, like any other atoms, are mostly empty space

Front 46

Generally speaking, the larger a nucleus is, the greater its

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instability

Front 47

The half life of an isotope is one day. At the end of three days, how much of the isotope remains?

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one eighth

Front 48

According to Niels Bohr, an electron in an excited state could give off

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several photons in a series of transitions to the ground state

Front 49

The Bohr model of the atom is similar to

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a miniature solar system

Front 50

We now consider the Bohr model of the atom to be

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defective and oversimplified but useful

Front 51

Compared to the average diameter of a hydrogen atom, the average diameter of a helium atom is

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smaller

Front 52

Heavy atoms are not appreciably larger in size than light atoms because the nuclei of heavy atoms have more

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electric charge

Front 53

What is it that electrons have that protons always have in equal magnitude?

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charge

Front 54

X-rays may be regarded as

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high frequency radio waves

Front 55

In the Heliocentric World System

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the sun is at the center of the universe and planets revolve around it

Front 56

According to Newton, gravitation is

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a universal attractive force

Front 57

According to the Big Bang Model,

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the universe is expanding

Front 58

Dark Energy is thought to be

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the cause of the acceleration of the universe

Front 59

Which of these electromagentic waves has the shortest wavelength?

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X-rays

Front 60

When visible light is incident upon clear glass, atoms in the glass

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are forced into vibration

Front 61

Infrared waves are often called heat waves because they

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induce resonance in molecules and increase internal energy in a substance

Front 62

Sunburns are produced by

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ultraviolet light

Front 63

Which of the following can not travel a vacuum?

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a sound wave

Front 64

A pair of sunglasses and a pair of reading glasses are left in the sunlight. The hotter glasses would be the

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sunglasses

Front 65

The color of an opaque object is the same as the light that is

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reflected

Front 66

What color light is transmitted by a piece of blue glass?

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blue

Front 67

Complimentary colors are two colors that

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produce white light when added together

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Different colors of light correspond to different light

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frequencies

Front 69

A mixture of cyan and yellow pigments appears

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green

Front 70

The sky is blue because air molecules in the sky act as tiny

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resonators which scatter blue light

Front 71

Red sunsets are due to lower frequencies of light that

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survive being scattered in the air

Front 72

The greenish blue of water is evidence for the

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absorption of red light

Front 73

According to Huygen's Principle, every point on a wave

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behaves as a source of new waves

Front 74

Polarization is a property of

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transverse waves

Front 75

Light will not pass through a pair of polaroids when their aces are

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perpendicular

Front 76

Monochromatic light is light of a single

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wavelength, frequency, and color

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Light from a lit match comes from

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electrons

Front 78

Light is emitted when an electron

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makes a transition to a lower energy level

Front 79

Compared to the energy put into a laser, the energy of the laser beam is

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less

Front 80

In the process of fluorescence, part of the input energy immediately

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becomes internal energy and the rest lower frequency light

Front 81

Light from a laser is

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monochromatic, in phase, and coherent

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A watch dial that continues to glow after a week in the dark is almost certainly

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radioactive

Front 83

The size of the pupil of your eye depends on

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your mood and the brightness of the room