Chapter 4 HW

Based on the above graph, which of these types of light from astronomical sources are not observable from the ground?

infrared at 100 micrometer (10-4 m) X-ray ultraviolet at 100 nm gamma ray

The resolution of radio telescopes suffers greatly from the large wavelengths of the light they are observing. What can be done to a radio telescope to improve its angular resolution?

make its dish bigger

Study the figure, which shows how someone on Earth can view Jupiter's moon's eclipses when Earth is closer to or farther from Jupiter, and determine which of the following are correct.

If light has infinite speed, an eclipse would be seen to happen at the same time regardless of how far away Earth is from Jupiter. If light has finite speed, it would take longer for it to travel from Jupiter to Earth when Earth is farther from Jupiter.

Which of the following statements best describes your observations of the arrow when the glass is filled with water?

It appears larger, and its direction is inverted.

Why is the Hubble Space Telescope in space instead of on the ground?

It avoids atmospheric distortion. It observes in the UV.

If the integration time is long enough to collect the light from this entire animation, what effect would seeing have on the image of the object?

It would blur the light from the object, effectively increasing the angular resolution of the telescope.

Imagine decreasing the size of the lens in the figure above. Which choice below best describes what would happen?

Less total light from the source will hit the lens, making it appear fainter on the detector.

Besides adding adaptive optics to a telescope, what else can be done to reduce the effects of seeing?

Put the telescope at a higher altitude (the height above sea level).

Is the amplitude related to the wavelength or frequency?

The amplitude is not related to the wavelength or the frequency.

Choose all of the effects that would automatically happen if the wavelength of light were increased.

The energy of the light would decrease. The frequency of the light would decrease.

If you had a telescope with the same-sized lens (and same focal length) as the human eye, what would be the benefit of taking an exposure of a steady light source with an integration time of 10 seconds?

The light source would appear brighter in the image.

Increase the wavelength, using the arrow key. What happens to the rate of the frequency counter?

The rate of the frequency counter decreases.

Based on the time frames given in the above figure, which of the following are implications of the finite speed of light?

When we gaze at the Andromeda Galaxy, we are looking back in time to the way it used to appear millions of years ago. There would be a noticeable delay in communications at the speed of light between Earth and astronauts on the Moon. If the light of the Sun were suddenly extinguished, we wouldn't notice it from Earth for over 8 minutes.

Here we will explore the following questions: How many properties does a wave have? Are any of these related to each other? Work your way through to the experimental section, where you can adjust the properties of the wave. Watch the simulation for a moment to see how fast the frequency counter increases. Reset the simulation, and increase the frequency. Did the wavelength change in the expected way based on the relationship between wavelength and frequency?

Yes. The wavelength decreased as expected.

The resolution of the human eye is 1 arcminute, or 1/60th of a degree. If the light of two street lamps in the distance is separated by 0.5 arcminute, what will you see with your eyes?

a single light, with the combined brightness of each street lamp

The angular resolution of a ground-based telescope is usually determined by

atmospheric seeing.

Rank each color of the rainbow by how much energy is carried by its electromagnetic waves, from highest to lowest.

blue yellow orange red

The amplitude of a light wave is related to its:

brightness

A light wave does not require:

medium

Rank the following in order of decreasing wavelength.

radio waves infrared visible ultraviolet gamma rays

The advantage of an interferometer is that

the resolution is dramatically increased

Which of the following can be observed from Earth's surface?

visible light radio waves