Physics Chapter 28 and 33 Quiz

Questions and Answers

What change in atomic number occurs when a nucleus emits an alpha particle?

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What change in atomic number occurs when a nucleus emits a beta particle?

What change in atomic number occurs when a nucleus emits a gamma ray?

What is the long-range fate of all the uranium that exists in the world?

it will turn into lead Signup and view all the answers

When, and by whom, did the first successful intentional transmutation of an element occur?

Ernest Rutherford, 1919 Signup and view all the answers

What occurs when a nitrogen nucleus captures an extra neutron?

None of the above. Signup and view all the answers

Which is more prevalent in the food we eat: carbon-12 or carbon-14?

There is about one carbon-14 atom for every 100 billion carbon-12 atoms. Signup and view all the answers

Why is lead found in all deposits of uranium ore?

Uranium undergoes radioactive decay, transmuting into lead. Signup and view all the answers

X-rays are most similar to which of the following - alpha, beta, or gamma rays?

gamma rays Signup and view all the answers

Which type of radiation - alpha, beta, or gamma - predominates within an enclosed elevator descending into a uranium mine?

gamma Signup and view all the answers

Rank these three types of radiation by their ability to penetrate a page of a book, from greatest penetration to least: gamma ray, beta particle, alpha particle.

C,B,A Signup and view all the answers

What happens to the image of a candle when the lower half of a concave mirror is covered with black tape?

The entire image would remain but would become dimmer. Signup and view all the answers

One ray of light reflecting off a spherical concave mirror can be treated as __________.

an incident ray passing through the focal point. Signup and view all the answers

What type or types of image can be displayed on a screen?

real Signup and view all the answers

What is a true statement about virtual images?

A virtual image is formed at the position from which the rays appear to have originated. Signup and view all the answers

Where will the image be formed if an object is placed very far from a converging lens?

It will be very near the focal point on the opposite side of the lens. Signup and view all the answers

What position of an object will create a real image with a converging lens?

The object is very far from the lens. Signup and view all the answers

The blackness of the type on a page is due to _________.

absorption. Signup and view all the answers

Light travels a path from one location to another in the least _________.

time. Signup and view all the answers

Specular reflection is common in the light reflected from _________.

a mirror. Signup and view all the answers

A mirage is the result of atmospheric _________.

refraction. Signup and view all the answers

What changes when light is refracted?

speed. Signup and view all the answers

Dispersion of light from drops making up a rainbow has undergone refraction and internal _________.

reflection. Signup and view all the answers

A secondary rainbow in the sky is the result of a _________.

a double reflection in drops. Signup and view all the answers

Total internal reflection occurs when the speed of light in a material is _________.

less than the speed outside the material. Signup and view all the answers

A feature of a pinhole camera is that the image _________.

is inverted. Signup and view all the answers

A magnifying glass widens the angle through which _________.

an object is viewed. Signup and view all the answers

What discovery closely followed the discovery of X-rays?

The discovery of radioactivity. Signup and view all the answers

Which of these is considered electromagnetic radiation?

gamma radiation. Signup and view all the answers

Which of these comprises the least radiation in the everyday environment?

nuclear power plants. Signup and view all the answers

Which of these ejects into the atmosphere the greatest amount of dangerous radiation?

coal-fired power plants. Signup and view all the answers

Where does the strong force exist?

only between particles in the nucleus. Signup and view all the answers

If a certain isotope has a radioactive half-life of 10 years, how much of the isotope will remain at the end of 20 years?

one quarter. Signup and view all the answers

Which radiation detector converts flashes of light into electric signals?

Scintillation counter. Signup and view all the answers

What happens when an element undergoes radioactive decay?

It becomes an entirely different element. Signup and view all the answers

From what is Carbon-14 in the atmosphere transformed?

nitrogen. Signup and view all the answers

What will all the uranium in today's deposits become in the future?

lead. Signup and view all the answers

How does incident light on an object affect the motion of electrons in that object?

Incident light makes the electrons oscillate. The electrons then emit light or absorb the light and convert it to heat. Signup and view all the answers

What do the electrons do when they are made to vibrate with greater energy?

They reemit more light or collide with neighbors, thereby converting light energy to more internal energy. Signup and view all the answers

What is Fermat's principle of least time?

Light takes the quickest path in going from one place to another. Signup and view all the answers

What is the law of reflection?

The angle of incidence equals the angle of reflection. Signup and view all the answers

Relative to the distance of an object in front of a plane mirror, how far behind the mirror is the image?

The image is the same distance behind the plane mirror as the object is in front of it. Signup and view all the answers

What fraction of the light shining straight at a piece of clear glass is reflected from the first surface?

about 4%. Signup and view all the answers

Can a surface be considered polished for some waves and not for others? Cite an example.

Yes. The mesh of a radio dish is polished for long wavelength radio waves and yet rough for short wavelength light waves. Signup and view all the answers

What is astigmatism and how can it be corrected?

Astigmatism is caused when the cornea has a different radius of curvature in one direction compared to another. It is cured by adding a lens with a different radius of curvature in two different directions. Signup and view all the answers

How do the angles compare for a ray of light striking a pane of window glass versus exiting?

The angles are the same. Signup and view all the answers

When is the angle at which a ray of light strikes glass not the same as the angle it exits?

When the light strikes the glass in one medium (such as air) and exits the glass in another medium (such as water). Signup and view all the answers

In which medium does light travel faster - thin air or dense air? How does this affect the length of daylight hours?

It travels faster in thin air, which makes sunlight curve and extends the length of the day. Signup and view all the answers

Does the law of reflection hold for curved mirrors? Explain.

Yes. It is as if the curved mirror is made of many small plane mirrors at slightly different orientations to each other. Signup and view all the answers

Is a mirage the result of reflection or refraction? Why does it happen?

Refraction. Light curves through warm, low-density air near the ground, where it travels faster. Signup and view all the answers

What slows light when it passes from air into glass or water?

The light oscillates electrons in the atoms of the glass or water. The electrons absorb some of the energy and reemit it after a delay at each atom. Signup and view all the answers

What is the angle between a light ray and its wavefront?

a right angle. Signup and view all the answers

What is the relationship between index of refraction and the speed of light in a material?

The index of refraction is inversely proportional to the speed of light in a material. Signup and view all the answers

Are eyeglasses made with high index of refraction materials thinner or thicker? Why?

Thinner. Light bends more entering high index of refraction materials. Signup and view all the answers

How does refraction change the apparent depth of a swimming pool?

It makes the pool look shallower - only ¾ as deep. Signup and view all the answers

Which travels more slowly in glass, red light or violet light? Why?

Violet light travels slower because it is closer in frequency to the ultraviolet resonance of the atoms in the glass. Signup and view all the answers

Does a single raindrop illuminated by sunlight deflect light of a single color or does it disperse a spectrum of colors? Does it do this by reflection, refraction, or both?

It disperses a spectrum of colors, by both reflection and refraction. Signup and view all the answers

Does a viewer see a single color or a spectrum of colors coming from a single faraway drop?

A viewer sees a single color from a single faraway drop. Signup and view all the answers

Why is a secondary rainbow dimmer than a primary bow and how are the colors arranged?

There is a second reflection with a loss of light. The colors are in the opposite order of the primary bow, with red on the inside instead of the outside. Signup and view all the answers

What is meant by critical angle?

The minimum angle of incidence inside a medium where light is totally reflected. Signup and view all the answers

At what angle inside glass is light totally internally reflected?

43°. Signup and view all the answers

What angle inside a diamond is light totally internally reflected?

24.5°. Signup and view all the answers

Why does light 'bend' in an optical fiber?

Total internal reflection keeps the light trapped inside the optical fiber. Signup and view all the answers

Distinguish between a converging lens and a diverging lens.

When two parallel rays pass through a converging lens, the rays bend towards each other. When they pass through a diverging lens, the rays move apart from each other. Signup and view all the answers

What is the focal length of a lens and what is the focal point?

The focal length is the distance between the center of the lens and either focal point. The focal point is where a beam of parallel light converges. Signup and view all the answers

Distinguish between a virtual image and a real image.

A virtual image cannot be displayed on a screen and is upright, whereas a real image is inverted. Signup and view all the answers

What kind of lens can be used to produce a real image? A virtual image?

A real image can only be made with a converging lens. A virtual image can be made with either a converging or diverging lens. Signup and view all the answers

Why is vision sharpest when the pupils of the eye are very small?

Light passes only through the center of the lens, where aberrations are minimal. Signup and view all the answers

When a flashlight submerged in water shines up into the air, does the speed of light increase or decrease?

increases. Signup and view all the answers

How many mirrors are involved in the multiple images of physics teacher Karen Jo Matsler?

three mirrors. Signup and view all the answers

Which numbered card can Karen Jo Matsler see reflected in the mirror?

<ol start="2"> <li></li> </ol> Signup and view all the answers

If a nearsighted person wants thinner eyeglasses, is a higher or lower index of refraction recommended?

higher. Signup and view all the answers

Do waves overlap in the image of a pinhole camera?

No, this feature contributes to sharpness. Signup and view all the answers

When wheels from a toy cart are rolled from concrete to grass, which surface causes the most bending?

B,C,A. Signup and view all the answers

How does the light ray bend toward the normal in different materials (A, B, C)?

C,B,A. Signup and view all the answers

A butterfly is 16 cm in front of a plane mirror. How far is your eye from its image?

66 cm. Signup and view all the answers

What percentage of light is transmitted through a pane of window glass?

91%. Signup and view all the answers

What light percentage is transmitted by a double-paned window?

84%. Signup and view all the answers

If the Sun makes an angle of 0.53° from Earth, how long does it take to move one solar diameter?

2.1 minutes. Signup and view all the answers

What did Wilhelm Roentgen discover about a cathode-ray beam striking a glass surface?

It produced X-rays. Signup and view all the answers

What kind of rays are X-rays?

electromagnetic. Signup and view all the answers

What did Henri Becquerel discover about uranium?

Uranium emitted radiation that would expose film and could be deflected by electric and magnetic fields. Signup and view all the answers

What two elements did Pierre and Marie Curie discover?

Polonium and radium. Signup and view all the answers

Why aren't gamma rays deflected in a magnetic field?

Gamma rays are electromagnetic radiation and have no charge. Signup and view all the answers

Which has the higher frequency: X-rays or gamma rays?

Gamma rays. Signup and view all the answers

Distinguish between a rad and a rem.

A rad measures energy absorbed, whereas a rem measures biological damage done. Signup and view all the answers

Do humans receive more radiation from artificial or natural sources?

Natural, about 80%. Signup and view all the answers

Is the human body radioactive? Explain.

Yes. The potassium in our bodies has a radioactive isotope that is the main internal source of radiation for a human body. Signup and view all the answers

What is a radioactive tracer?

A radioactive isotope of an element used to trace biochemical pathways in plants and organisms. Signup and view all the answers

Name the two different nucleons.

Proton and neutron. Signup and view all the answers

Why doesn't the repulsive electrical force of protons in the atomic nucleus cause them to fly apart?

The attractive strong nuclear force holds the nucleus together. Signup and view all the answers

Why is a larger nucleus generally less stable than a smaller nucleus?

The electric force of repulsion between protons is a long-range force, while the attractive strong nuclear force is short-range. Signup and view all the answers

What is the role of neutrons in the atomic nucleus?

Neutrons contribute strong nuclear force attraction without adding electric force repulsion. Signup and view all the answers

Which contains the higher percentage of neutrons: large nuclei or small nuclei?

Large nuclei (more than 50%). Signup and view all the answers

How does the rate of decay of a long-half-life material compare to that of a short-half-life material?

The rate of decay is lower for a long-half-life material. Signup and view all the answers

What is the half-life of Ra-226?

1620 years. Signup and view all the answers

What kind of trail is left when an energetic particle shoots through matter?

A trail of free electrons and positive ions. Signup and view all the answers

Which type of detector senses radiation by ionization of gas in a tube?

Geiger counter. Signup and view all the answers

Which type of detector senses flashes of light produced by charged particles or gamma rays?

Scintillation counter. Signup and view all the answers

What is transmutation? Give one example.

The change of one chemical element into another, such as uranium to lead. Signup and view all the answers

When thorium decays by emitting an alpha particle, what is the atomic number of the resulting nucleus?

<ol start="88"> <li></li> </ol> Signup and view all the answers

When thorium decays by emitting a beta particle, what is the atomic number of the resulting nucleus?

<ol start="91"> <li></li> </ol> Signup and view all the answers

What is the change in the atomic mass number for each of the reactions?

The atomic mass number decreases by 4 for alpha decay and increases by 1 for beta decay. Signup and view all the answers

Study Notes

Image Formation and Reflection

Covering the lower half of a concave mirror causes the image to remain visible but appear dimmer.
An incident ray from a candle flame reflects off a concave mirror, passing through the focal point.
Real images can be displayed on screens like paper; they are formed by converging light rays.

Image Types

Virtual images are always formed at positions where light rays appear to originate and cannot be displayed on a screen.
Real images are inverted compared to the original object and can be formed by converging lenses or mirrors.

Light Behavior

The blackness on a page is due to absorption, where light is taken in rather than reflected or transmitted.
Light travels in the least time possible, which governs its path.

Reflection and Refraction

Specular reflection occurs with mirrors, causing clear reflections.
A mirage is caused by atmospheric refraction, where light bending creates an illusion of water on hot surfaces.
Refraction changes the speed of light, causing light to bend at different angles when passing through materials like water or glass.

Lenses and Optical Instruments

A pinhole camera produces inverted images with sharp definition due to no overlapping waves.
A magnifying glass widens the angle of view, making images appear larger.
Converging lenses can create real images when the object is far away, while diverging lenses create virtual images.

Radiation and Radioactivity

X-rays and gamma rays are forms of electromagnetic radiation, with gamma rays possessing higher frequency.
Radioactivity is typically associated with certain isotopes; elements that undergo decay transform into entirely different substances.
Natural sources provide the majority of radiation exposure to humans, with potassium acting as a primary internal source.
Detection of radiation can occur through devices like Geiger counters and scintillation counters, which measure different interactions.

Atomic Structure

The strong nuclear force keeps protons within an atomic nucleus from repelling each other due to electrical force.
Larger atomic nuclei tend to be less stable due to the balance of electric repulsion and strong force.
Neutrons help stabilize atomic nuclei by providing strong nuclear force without contributing to repulsion.

Transmutation and Isotopes

Transmutation is the conversion of one element into another, exemplified by uranium decaying into lead.
Carbon-14 is present in very small quantities compared to carbon-12, influencing dating methods.

General Principles

When light passes at different angles between materials, it bends; this bending is governed by the index of refraction, which relates to the material’s density.
Observations involving multiple mirrors or reflections reveal properties of light, such as symmetry and properties of real versus virtual images.
The angle of incidence and angle of reflection are equal at reflective surfaces, reinforcing fundamental laws of optics.

Practical Applications and Phenomena

The understanding of angle relationships and behaviors of light rays is crucial in designing lenses for glasses, cameras, and various optical devices.
Real-world applications include addressing vision issues such as astigmatism with specially designed corrective lenses.

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Description

Test your understanding of concepts covered in Chapters 28 and 33 of physics. This quiz includes questions related to concave mirrors and the behavior of light. Analyze the effects of altering the mirror setup on image formation.