Physics Ch 33

When the flashlight is in the air and the refracted ray enters the water, how does the angle of refraction compare with the angle of incidence?

The angle of refraction is smaller than the angle of incidence, other than when the flashlight is on the normal line.

When the flashlight is in the air and the refracted ray is in the water, what happens to the angle of refraction if you increase the angle of incidence?

The angle of refraction increases

When the flashlight is in the water and the refracted ray enters the air, how does the angle of refraction compare with the angle of incidence?

The angle of refraction is greater than the angle of incidence

When the flashlight is in the water and the refracted ray is in the air, what happens to the angle of refraction if you increase the angle of incidence?

The angle of refraction increases.

Specular reflection is common in the light reflected from _________.

A mirror

How does the angle at which a ray of light strikes a pane of window glass compare with the angle at which it passes out the other side?

The angles are the same

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)

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.

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.

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.

A mirage is the result of atmospheric _________

Refraction

When the wheel of a cart rolls from a smooth sidewalk onto a plot of grass, the interaction of the wheel with the blades of grass slows the wheel. 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.

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.

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

Thinner. Light bends more entering high index of refraction materials.

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

It makes the pool look shallower – only ¾ as deep.

When a car veers off the road such that the left front wheel goes off the pavement into the gravel before the right wheel, what will happen to the car, and why?

The car will tend to turn to the left. Because the left wheel hits the gravel first and slows down before the right wheel, the right wheel covers a greater distance, causing the car to turn to the left.

What is the relationship between the direction of traveling rays of light and the line representing the wave crests?

The direction of the rays of light is perpendicular to the line representing the wave crests.

What happens to the speed of light waves when they enter water from air?

The speed decreases.

What happens to the wavelength and frequency of the light waves as they enter water from air?

Wavelength decreases, and frequency will stay the same

Which of the following changes when light is refracted?

Speed

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.

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

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.

Why is a secondary rainbow dimmer than a primary bow? How are the colors arranged in the secondary bow?

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.

When white light strikes a prism, what happens and why?

The white light emerges with the colors separated, with the red light bending the least.

Why does a rainbow look like a curve when viewed from the ground?

Raindrops act like prisms that reflect the colors of light in particular angles depending on how the individual colors are bent by the prism. Light seen at that angle forms a bow shape.

What would the rainbow look like to a viewer in the sky, and why?

The rainbow would appear to be a complete circle, because Earth no longer obstructs our view when we are above.

What kind of glasses would you wear while watching 3D movies, and why?

glasses with one horizontally polarized and one vertically polarized lens, because one projector is horizontally polarized and the other is vertically polarized

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

Reflection

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

a double reflection in drops

What is it meant by critical angle?

The minimum angle of incidence inside a medium where light is totally reflected

At what angle inside glass is light totally internally reflected? At what angle inside a diamond is light totally internally reflected?

43 degrees 24.5 degrees

Light normally travels in straight lines, but it "bends" in an optical fiber. Explain.

Total internal reflection keeps the light trapped inside the optical fiber.

If two convex lenses identical in size and shape are manufactured from glass with two different indices of refraction, would the focal length of the lens with the greater index of refraction (lens 1) be larger or smaller than that of the other lens (lens 2)?

Smaller

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

Less than the speed outside the material

Distinguish between a converging lens and a diverging lens.

When two parallel rays of light 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.

Distinguish between a virtual image and a real image. Mention in each case whether the image made by a single lens is right-side up or inverted.

A virtual image, unlike a real image, cannot be displayed on a screen. A virtual image is upright, whereas a real image is inverted.

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.

The energy of a photon is related to:

The energy given to the atom that emits it. Its frequency And the energy level difference through which it falls

An atom that absorbs a photon of a certain energy can then emit

Only a photon of the same or lower energy

A certain object emits infrared waves. If it were to emit light waves instead, its temperature would have to be:

Higher

Electrons with the greater potential energies with respect to the atomic nucleus are:

Outer electrons

Green light emitted by excited mercury vapor corresponds to a particular energy transition in the mercury atom. A more energetic transition might emit:

Blue light

Light is emitted when an electron:

Makes a transition to a lower energy level.

The variety of colors seen in a burning log comes from the variety of:

Electron transitions in various atoms.

The highest frequency light of those below is:

Violet

Fluorescent minerals on display in museums are illuminated with:

Ultraviolet light

A paint pigment that absorbs red light and gives off blue light:

Doesn’t exist

Atoms of neon in a glass tube can be excited:

Over and over again

The hottest star is that star that glows

Blue

The energy of a photon depends on its

Frequency

A convex lens has a focal length, F. An object is placed at a distance between F and 2F on a line perpendicular to the center of the lens. The image formed is located at what distance from the lens?

Farther than 2F

When a colored light in air shines on water and is refracted, its wavelength:

Shortens

As a solid is gradually heated, it first glows:

Red

When light passes through a common windowpane, its angle of emergence is:

The same as its angle of incidence

Rainbows exist because light is

Refracted AND reflected

If a certain object emits visible waves rather than infrared waves its temperature is:

Higher

When a light beam emerges from water into air, light speed:

Increases

The greater proportion of energy immediately converted to heat rather than light occurs in

An incandescent lamp

If a fish looks upward at 45 degrees to a pond’s water surface, it will see:

The sky and possibly some tall surroundings

A radio wave and a visible light wave differ only in

Frequency AND energy per photon

The superposition of identical wave affects

Amplitude

When ultraviolet energy is absorbed by an atom, an electron:

Moves from a lower to a higher energy level

When a pulse of white light is incident on a glass prism, the first color to emerge is:

Red

Thomas Young’s two-source interference patterns demonstrate the:

Wave nature of light

The type of lens that spreads parallel light is a:

Diverging lens

Light refracts when traveling from air into glass because of a change in light’s

Speed

When light is refracted, there is a change in its

Wavelength

The white light emitted by a fluorescent light is provided by the

Phosphors on the inner surface of the lamp

If an object is place inside the focal point of a diverging lens, the image is

Virtual, upright and reduced

The major difference between phosphorescent and fluorescent materials is

A time delay excitation and de excitation

When a light ray in air enters water at 15 degrees from the normal, it:

Always bends TOWARDS the normal

Diffraction from foghorns is best if the waves being diffracted are:

Long

Which light-emitting process is characterized by an afterglow?

Phosphorescence

Polarization is a property of

Transverse waves

Atoms can be excited by

Electrons impacts, thermal agitation, and photon impact

An atom that emts light of a certain frequency is

An absorber of light of the same frequency

An object is placed in front of a lens, which forms an image of the object?

If the image is real, then it is also inverted

Atomic emission spectra are due to electrons

In an atom dropping from one energy level to a lower one

The energy of an infrared photon is higher than that of

A microwave photon

As the filament of a lamp is heated, it changes:

Temperature and color

Refraction occurs when light passing from one medium to another:

Changes speed

Light of different colors in a glass prism travel at

Different speeds

The fanning out of waves upon passing through an opening is more pronounced through

Small openings

The highest frequency of visible light is:

Violet

Monochromatic light is light of a single:

Color, frequency and wavelength

An atom is excited when one or more of its electrons

Is boosted into higher energy levels

The average speed of light is greatest in

Red glass

When waves from a pair if closely spaced slits arrive in phase:

A bright fringe is produced

The critical angle fro a transparent material is the angle at and beyond which all light within the material at its upper surface is

Reflected

The separation between adjacent maxima in a double slit interference pattern using monochromatic light is

Greatest for red light