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