Exploring the Cosmos - Degree Exam 2013 - Mapping the universe
1. A Schmidt-Cassegrain telescope is one that has?
Only mirrors.
A corrector plate, a primary mirror and a secondary mirror.
A corrector plate and a primary mirror only.
Only lenses.
2. Why are astronomers interested in measuring light at different parts of the electromagnetic spectrum?
Because in vacuum light travels at different speeds at different wavelengths.
Different parts of the spectrum provide different information.
Stars emit mainly ultraviolet radiation.
Because visible light is hard to detect on Earth.
3. What does the frequency of light mean?
How bright the light will be.
The distance from one maximum to another.
The distance it will travel in 1 second.
The number of times the wave cycle repeats every second.
4. The energy of a photon can be expressed by
E=cλ.
E=hc.
E=hf.
E=f/λ.
5. What is the purpose of the objective lens in a refracting telescope?
To focus the incoming light.
To change the speed of the incoming light.
To interfere the incoming light.
To diffract the incoming light.
6. If a refracting telescope has an objective lens with a focal length of 300cm and has an eyepiece with a focal length of 3cm, the magnification is?
M = 3/300.
M = 1/100.
M = 100.
M = 300.
7. Active optics is used in modern telescopes to
change the detector sensitivity for measuring different wavelengths.
maximise the light gathering power of the telescope.
change the focal length of the primary mirror for different astronomical objects.
change the shape of the primary mirror to correct for atmospheric disturbances.
8. The Earth’s atmosphere is responsible for which three phenomena in observational astronomy?
Atmospheric scattering, Spherical aberration, and Atmospheric refraction.
Atmospheric diffraction, Chromatic aberration, and Atmospheric scattering.
Atmospheric refraction, Atmospheric scattering, and Atmospheric absorption.
Wave particle duality, Atmospheric scattering, and Atmospheric absorption.
9. For what reason is interferometry used when using multiple telescopes to observe astronomical objects?
To reduce the magnification.
To measure different frequencies of light simultaneously.
To increase the resolving power of the detector.
To remove the effect of light pollution.
10. Gravitational wave detectors aim to measure the radiation emitted by accelerating masses by
using the James Webb Space Telescope.
using multiple radio telescopes around the world.
detecting Cherenkov radiation with photomultiplier tubes.
using long-baseline laser interferometers.
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