Podcast
Questions and Answers
What is the wavelength of the longest wavelength light visible to the human eye?
What is the wavelength of the longest wavelength light visible to the human eye?
- 7000 nm
- 4000 nm
- 700 nm (correct)
- 400 nm
What type of radiation has wavelengths longer than visible light?
What type of radiation has wavelengths longer than visible light?
- X-rays
- Gamma-rays
- Ultraviolet light
- Infrared radiation (correct)
What happens to ultraviolet radiation from a star?
What happens to ultraviolet radiation from a star?
- It has a wavelength that is shorter than the x-rays emitted by the star.
- It will penetrate Earth's atmosphere and reach the ground.
- It has a wavelength that is longer than the visible light emitted by the star.
- It will not penetrate Earth's atmosphere and reach the ground. (correct)
What is the wavelength of violet light?
What is the wavelength of violet light?
How many nanometers are in one meter?
How many nanometers are in one meter?
What is the ratio of the light gathering power of a 5-m telescope to that of a 0.5-m telescope?
What is the ratio of the light gathering power of a 5-m telescope to that of a 0.5-m telescope?
What is the magnification of a telescope and eyepiece if the telescope objective has a focal length of 200 cm and the eyepiece has a focal length of 0.2 cm?
What is the magnification of a telescope and eyepiece if the telescope objective has a focal length of 200 cm and the eyepiece has a focal length of 0.2 cm?
Why do radio telescopes have poor resolving power?
Why do radio telescopes have poor resolving power?
What does CCD stand for in astronomy?
What does CCD stand for in astronomy?
Which of the following types of electromagnetic radiation can penetrate the Earth's atmosphere to reach its surface?
Which of the following types of electromagnetic radiation can penetrate the Earth's atmosphere to reach its surface?
What is the reason why the Hubble Space Telescope objective mirror is not affected by the Earth's atmosphere?
What is the reason why the Hubble Space Telescope objective mirror is not affected by the Earth's atmosphere?
What is the main reason for building large optical telescopes on the Earth's surface?
What is the main reason for building large optical telescopes on the Earth's surface?
Why does the Spitzer Space Telescope orbit far from Earth?
Why does the Spitzer Space Telescope orbit far from Earth?
What is the correct description of refraction of light?
What is the correct description of refraction of light?
What is the light-gathering power of a telescope directly proportional to?
What is the light-gathering power of a telescope directly proportional to?
What is the main advantage of building large telescopes?
What is the main advantage of building large telescopes?
What is the main reason for putting telescopes in space?
What is the main reason for putting telescopes in space?
In which type of telescope does chromatic aberration occur when different colors of light do not focus at the same point?
In which type of telescope does chromatic aberration occur when different colors of light do not focus at the same point?
What is the main reason for combining the signals of multiple radio telescopes across a large area?
What is the main reason for combining the signals of multiple radio telescopes across a large area?
What type of telescope has a mirror as its objective?
What type of telescope has a mirror as its objective?
Which of the following telescopes has a larger light-gathering power?
Which of the following telescopes has a larger light-gathering power?
Why is it not a good idea to position radio telescopes close together?
Why is it not a good idea to position radio telescopes close together?
What is the characteristic of a refracting telescope?
What is the characteristic of a refracting telescope?
What is a common feature of new telescopes?
What is a common feature of new telescopes?
What is the ability of a telescope to resolve fine detail known as?
What is the ability of a telescope to resolve fine detail known as?
Why is infrared astronomy often done from high-flying aircraft?
Why is infrared astronomy often done from high-flying aircraft?
What technique uses a high-speed computer to monitor atmospheric distortion and adjust the optics of a telescope?
What technique uses a high-speed computer to monitor atmospheric distortion and adjust the optics of a telescope?
What is a measure of a telescope's ability to show fine detail?
What is a measure of a telescope's ability to show fine detail?
What type of telescope is most likely to suffer from chromatic aberration and have a low light gathering power?
What type of telescope is most likely to suffer from chromatic aberration and have a low light gathering power?
Study Notes
Visible Light
- The longest wavelength of visible light is approximately 700 nm.
- The shortest wavelength of visible light is approximately 400 nm.
- Violet light has a wavelength of approximately 400 nm.
Electromagnetic Radiation
- Infrared radiation has a longer wavelength than visible light.
- Ultraviolet radiation has a shorter wavelength than visible light.
- Gamma-rays have a shorter wavelength than X-rays.
- Radio waves have a longer wavelength than visible light.
Telescopes
- Astronomers build optical telescopes on top of mountains because there is less air to dim the light and the seeing is better.
- The light-gathering power of a telescope is directly proportional to the diameter of the primary mirror or lens.
- The resolving power of a telescope is a measure of its ability to show fine detail and depends on the diameter of the objective.
- The magnification of a telescope is determined by the focal length of the telescope objective and the eyepiece.
Optical Telescopes
- Ultraviolet radiation from a star will not penetrate Earth's atmosphere and reach the ground.
- CCD stands for Charge-Coupled Device.
- Observations of radio waves from astronomical objects suffer from poorer resolution than visible observations because the wavelength of radio waves is much longer than the wavelengths of visible light.
Radio Telescopes
- Radio telescopes have poor resolving power because radio waves have long wavelengths.
- Radio waves can penetrate the Earth's atmosphere to reach its surface.
- The main reason for positioning many radio telescopes across a large area and combining the signals is to produce higher resolution images.
Space Telescopes
- The Hubble Space Telescope objective mirror is not affected by bad seeing or chromatic aberration.
- The Spitzer Space Telescope orbits very far from Earth because the Earth thermally emits infrared radiation, which the telescope is also constructed to observe.
Refraction and Reflection
- Refraction is the change in direction of a light ray as it passes to a medium of different optical density.
- Chromatic aberration occurs in a refracting telescope when different colors of light do not focus at the same point.
- A reflecting telescope uses a mirror as its objective, while a refracting telescope uses a lens.
Telescope Design
- The main reason for building large optical telescopes on the Earth's surface is to collect as much light as possible from faint objects.
- New telescopes use segmented mirrors, thin mirrors, and active optics to control the shape of the mirror.
- Adaptive optics is a technique that uses a high-speed computer to monitor atmospheric distortion and adjust the optics of a telescope to partially compensate for the seeing.
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Description
Practice your understanding of astronomy with this review quiz, covering topics such as wavelengths of light, including visible and non-visible spectra. Test your knowledge with multiple-choice questions and see how well you've mastered the material. Ideal for students studying astronomy and physics.