What is light?

Match the following speeds with their corresponding values in m/s.

• Approximate speed of light in m/s

• 300,000,000

• Average distance from Earth to Sun in meters per second

• 250,000,000

• Speed of light in vacuum

• 150,000,000

• Hypothetical speed

• 299,792,458

Answer explanation

Light in a vacuum travels at a constant speed of 299,792,458 m/s, which is the exact value defined in physics. The other options are approximations or incorrect.

Emily is observing a rainbow and notices that the colors change from red to violet. What happens to the energy of light as the wavelength becomes shorter?

• The energy increases.

• The energy decreases.

• The energy remains the same.

• The energy is converted to sound.

Answer explanation

As the wavelength of light decreases, its energy increases. This relationship is described by the equation E = hc/λ, where E is energy, h is Planck's constant, c is the speed of light, and λ is the wavelength.

Which of the following colors is not a part of the visible spectrum shown in the diagram?

• Red

• Orange

• Black

• Violet

Answer explanation

Black is not a part of the visible spectrum, which includes colors like red, orange, and violet. The visible spectrum consists of light that can be seen by the human eye, while black represents the absence of light.

Fill in the blank: Incandescent light is produced as a result of _________.

• heating a filament

• chemical reaction

• nuclear fusion

• magnetic field

Answer explanation

Incandescent light is produced by heating a filament until it glows. This process occurs in traditional light bulbs, making 'heating a filament' the correct answer, while the other options do not relate to incandescent light production.

Which of the following is an example of incandescent light?

Answer explanation

An example of incandescent light is a traditional light bulb, which produces light by heating a filament until it glows. This is in contrast to other types of lighting, such as LED or fluorescent, which use different mechanisms.

The process by which electric discharge produces light is called:

• Incandescence

• Luminescence

• Electroluminescence

• Phosphorescence

Answer explanation

Electroluminescence is the process where electric discharge causes materials to emit light. This distinguishes it from other forms of light production like incandescence and luminescence, making it the correct choice.

Which of the following is an application of fluorescent lights?

• Black lights

• Tanning lamps

• Germicidal lamps

• All of the above

Answer explanation

Fluorescent lights are used in various applications, including black lights for detecting fluorescent materials, tanning lamps for UV exposure, and germicidal lamps for sterilization. Therefore, the correct answer is 'All of the above'.

Which of the following organisms can produce bioluminescence?

• Algae

• Jellyfish

• Fish

• All of the above

Answer explanation

All of the listed organisms—algae, jellyfish, and fish—are known to produce bioluminescence. This natural phenomenon occurs in various species across these groups, making 'All of the above' the correct answer.

How do light-emitting diodes (LEDs) produce light?

• By heating a filament until it glows

• By passing current through a semiconductor

• By chemical reaction

• By using a gas discharge

Answer explanation

LEDs produce light by passing current through a semiconductor. This process excites electrons, causing them to release energy in the form of light, unlike traditional methods that rely on heating or gas discharge.

While we watch the Bill Nye Video on Light and Colour, add to your note anything you find interesting or that helps with your understanding of the concepts we are looking at.

• Add interesting points from the video.

• Ignore the video content.

• Write unrelated notes.

• Focus on other subjects.

Answer explanation

The correct choice is to add interesting points from the video, as this enhances understanding of light and color concepts. Ignoring the video or writing unrelated notes does not contribute to learning.