Question 1

Using three similarities and three differences please compare and contrast fluorescent light bulbs and high pressure sodium lamps.

Accepted Answer

The answer of Using three similarities and three differences please...

Question 2

"Laser" stands for
A) light amplification through stimulated emission of radiation.
B) light attenuation through stimulated emission of radiation.
C) light amplification through spontaneous emission of radiation
D) let's all study electromagnetic waves and refraction.

Accepted Answer

"Laser" stands for Light Amplification by Stimulated Emission of Radiation, which is accurately described in option A.

Question 3

Laser light is
A) polarized.
B) coherent.
C) incoherent.
D) incandescent.

Accepted Answer

The answer of Laser light is
A) polarized.
B) coherent.
C) incoherent.
D) incandescent....

Question 4

Three different lasers are emitting steady beams of light. Each beam consists of countless copies a single original photon of light. However, not all colors can be emitted by a laser. Which of the following choices is possible for these three lasers?
A) Yellow, green, and blue light
B) Green, blue, and white light
C) Blue, white, and yellow light
D) White, yellow, and green light

Accepted Answer

Lasers emit light of a specific wavelength, corresponding to a specific color. White light is a combination of all visible wavelengths and cannot be emitted by a single laser, which rules out choices B, C, and D.

Question 5

Laser light exhibits much stronger interference effects than light from a flashlight. This is because
A) laser light has a much shorter wavelength than light from a flashlight.
B) laser light is both coherent and monochromatic.
C) laser light carries much more energy than light from a flashlight.
D) laser light travels as waves while light from a flashlight travels as particles.

Accepted Answer

Laser light is coherent, meaning the light waves are in phase with each other, and monochromatic, meaning they have a single wavelength. These properties enable laser light to exhibit strong interference effects, unlike the incoherent and polychromatic light from a flashlight.

Question 6

In a typical laser, the right color of light bounces back and forth between two mirrors and
A) is ignored by the laser medium.
B) is amplified by the mirrors.
C) is amplified by the excited atoms in the laser medium.
D) is de-amplified by the laser medium.

Accepted Answer

In a typical laser, the right color of light is amplified by the excited atoms in the laser medium. This process is known as stimulated emission, where the excited atoms in the laser medium release additional photons that are coherent with the photons already present, effectively amplifying the light.

Question 7

When laser light reflects from a soap bubble, its photons can interfere with one another. In contrast, when sunlight reflects from a soap bubble, each photon can interfere only with itself. The reason for this difference is that
A) the photons in a laser beam are all part of a single wave, while those in sunlight are independent waves.
B) the photons in a laser beam have both electric and magnetic fields, while those in sunlight have only electric fields.
C) the photons in a laser beam have both electric and magnetic fields, while those in sunlight have only magnetic fields.
D) the photons in a laser beam are both vertically and horizontally polarized, while those in sunlight are only vertically polarized.

Accepted Answer

Laser light is coherent, meaning the photons are in phase and can act as a single wave, allowing them to interfere with each other. Sunlight, being incoherent, consists of independent waves, so each photon can only interfere with itself.

Question 8

A bright beam of light from a laser passes through a tiny pinhole on its way to a projection screen on the other side of the room. Since the beam was several millimeters in diameter, the pinhole blocks most of the beam's light. After passing through this pinhole, the remaining light
A) converges together rapidly to form an image of the laser on the projection screen.
B) forms an extremely narrow beam that illuminates only a tiny spot on the projection screen-a spot the same diameter as the pinhole.
C) changes frequency and color because it experiences destructive interference inside the pinhole.
D) spreads relatively rapidly so that it forms a rather large spot on the projection screen.

Accepted Answer

When light passes through a small aperture like a pinhole, it exhibits diffraction, which causes the light to spread out rather than staying in a narrow beam. This results in a larger spot on the projection screen than the original size of the pinhole.

Question 9

The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder
A) slows down the white light produced by the gas atoms inside the tube so that less of that white light reflects as it passes through the walls of the tube.
B) conducts electricity from one electrode to the other and emits visible light as current passes through it.
C) absorbs ultraviolet light and uses the energy from that light to produce visible light.
D) scatters the white light produced by the gas atoms inside the tube so that it is both vertically and horizontally polarized and doesn't cause glare.

Accepted Answer

The white powder on the inner surfaces of fluorescent lamp tubes is a phosphor coating. This coating absorbs ultraviolet light produced by the gas atoms when they are excited by electricity and then re-emits the energy as visible light, making the lamp's light output appear bright and visible to the human eye.

Question 10

Some fiber optic communication systems use laser amplification to boost the intensity of light pulses passing through an optical fiber. A short segment of laser amplifier fiber is spliced into the main fiber so that the light pulses must pass through the laser amplifier fiber on their way to their destination. The light emerging from the laser amplifier fiber is much brighter than it was when it entered. One interesting aspect of the light emerging from the laser amplifier fiber is that it
A) has the same color as the light entering the amplifier fiber.
B) is slightly redder than the light entering the amplifier fiber-its wavelength is longer.
C) is slightly bluer than the light entering the amplifier fiber-its wavelength is shorter.
D) travels faster than the light entering the amplifier fiber.

Accepted Answer

The light emerging from a laser amplifier in a fiber optic system retains the same color as the light entering the amplifier, meaning its wavelength remains unchanged. The amplification process increases the intensity of the light without altering its wavelength.

Question 11

Explain why lasers can be used to perform surgery and cut through metal while incandescent light cannot.

Accepted Answer

The answer of Explain why lasers can be used to...

Question 12

Please consider the red helium - neon laser. Now let's say your boss wants you to make a green laser, or else she'll make you take all your physics classes over again. So, you really want to build this laser right, and you decide that the crucial issue is replacing the neon with another gas. You can choose from a gas (gas A) whose light producing electron energy levels are all closer together than neon's, or from another (gas B) whose light producing energy levels are all father apart than those of neon.
-Which gas would you chose? Please explain.

Accepted Answer

The answer of Please consider the red helium - neon...

Question 13

Please consider the red helium - neon laser. Now let's say your boss wants you to make a green laser, or else she'll make you take all your physics classes over again. So, you really want to build this laser right, and you decide that the crucial issue is replacing the neon with another gas. You can choose from a gas (gas A) whose light producing electron energy levels are all closer together than neon's, or from another (gas B) whose light producing energy levels are all father apart than those of neon.
-Now suppose your boss tricked you so that the mirrors in the laser did not reflect the green light - it just let the light through. Would this affect amplification and hence the brightness of the beam? Please explain.

Accepted Answer

The answer of Please consider the red helium - neon...

Question 14

Suppose you are a school teacher and are doing a demonstration on how lasers work by sending wave pulses down ropes. You have many students and enough ropes for each pair of students to have a rope. Please describe how you would do the demonstration.

Accepted Answer

The answer of Suppose you are a school teacher and...

Question 15

A laser diode's wavelength and color depend primarily on
A) the band gap of its power supply
B) what it is hooked up to
C) the band gap of its anode
D) the density of its anode

Accepted Answer

The wavelength and color of a laser diode depend primarily on the band gap of its anode material, which determines the energy of the photons emitted.

Question 16

White LEDs are
A) LEDs that emit white light.
B) ultraviolet LEDs with phosphors inside.
C) infrared LEDs that heat up phosphors
D) yellow LEDs with a white coating on the inside.

Accepted Answer

White LEDs are typically ultraviolet LEDs with phosphors inside that convert the UV light into visible white light.

Question 17

A CD reader uses laser light. What main difficulty would be encountered if white light were used?

Accepted Answer

The answer of A CD reader uses laser light. What...

Question 18

Suppose you view the light from an LED and from a laser diode through a prism. What would the main difference between the two types of light be?

Accepted Answer

The answer of Suppose you view the light from an...

Question 19

LED light is not damaging to your eye like a laser can be because
A) laser light is coherent while LED light is not.
B) laser light is monochromatic while LED light is not.
C) laser light is polarized.
D) laser light travels faster.

Accepted Answer

Laser light is coherent, meaning the light waves are in phase and can focus on a small area, causing potential damage. LED light is not coherent, so it spreads out and is less intense.

Question 20

A mercury street light gets brighter as it warms up because
A) the voltage across it is increasing.
B) the liquid mercury is flowing around more, making better connections.
C) more mercury is vaporizing.
D) it is getting darker outside and so it just looks brighter.

Accepted Answer

As the mercury street light warms up, more mercury vaporizes. The increased amount of mercury vapor allows for more efficient discharge processes, which in turn produces more light. This is why the light gets brighter as it warms up.

Quiz 13: Light

Using three similarities and three differences please compare and contrast fluorescent light bulbs and high pressure sodium lamps.

"Laser" stands for

Laser light is

Three different lasers are emitting steady beams of light. Each beam consists of countless copies a single original photon of light. However, not all colors can be emitted by a laser. Which of the following choices is possible for these three lasers?

Laser light exhibits much stronger interference effects than light from a flashlight. This is because

In a typical laser, the right color of light bounces back and forth between two mirrors and

When laser light reflects from a soap bubble, its photons can interfere with one another. In contrast, when sunlight reflects from a soap bubble, each photon can interfere only with itself. The reason for this difference is that

A bright beam of light from a laser passes through a tiny pinhole on its way to a projection screen on the other side of the room. Since the beam was several millimeters in diameter, the pinhole blocks most of the beam's light. After passing through this pinhole, the remaining light

The tubes in fluorescent lamps have a white powder on their inner surfaces. This powder

Explain why lasers can be used to perform surgery and cut through metal while incandescent light cannot.

Suppose you are a school teacher and are doing a demonstration on how lasers work by sending wave pulses down ropes. You have many students and enough ropes for each pair of students to have a rope. Please describe how you would do the demonstration.

A laser diode's wavelength and color depend primarily on

White LEDs are

A CD reader uses laser light. What main difficulty would be encountered if white light were used?

Suppose you view the light from an LED and from a laser diode through a prism. What would the main difference between the two types of light be?

LED light is not damaging to your eye like a laser can be because

A mercury street light gets brighter as it warms up because