Exploring the Cosmos - Class Test 1 - Mapping the Universe
1. Which of the following statements correctly describes the wavelength of an electromagnetic wave?
The wavelength is the distance travelled by the wave in a short time.
The wavelength is the distance between two consecutive peaks.
The wavelength is the distance travelled by the wave in 1 second.
The wavelength is the distance between a trough and a peak.
2. Why does a light ray bend when it crosses the boundary between two different media at an oblique angle?
Because the amplitude is reduced.
Because the frequency increases.
Because it interferes with the surface.
Because the speed of light changes.
3. A Newtonian telescope has
a correction plate
a flat secondary mirror
just the primary mirror
a diverging secondary mirror
4. As light passes from one medium to another, its direction of travel changes. What is the name of this effect?
Diffraction
Dispersion
Interference
Refraction
5. Diffraction gratings are used to
increase the resolution of telescopes.
break up light into a spectrum.
detect infrared radiation.
reduce diffraction of telescopes.
6. The speed of light in glass is
reduced by approximately 1%
reduced by approximately 60%
the same as in vacuum
increased by approximately 50%
7. Diffraction gratings are used for
analysing the light spectrum.
detecting microwave radiation.
increasing the angular resolution of telescopes.
reducing the diffraction of telescopes.
8. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Wavelength
Colour
Amplitude
Speed
9. Which of the following parameters is the same for all electromagnetic waves propagating in a vacuum?
Amplitude
Colour
Wavelength
Speed
10. Why does a light ray bend when it crosses the boundary between two different media at an oblique angle?
Because the speed of light changes.
Because the amplitude is reduced.
Because the frequency increases.
Because it interferes with the surface.
11. A Newtonian telescope has
a flat secondary mirror.
a correction plate.
just the primary mirror.
a diverging secondary mirror.
12. The Hubble telescope was placed in space in order
to not be limited by the Earth’s horizon.
to improve the magnification.
to be close to the stars.
to not be limited by the Earth’s atmosphere.
13. An electromagnetic wave with a wavelength of 600 nm is
infrared radiation.
microwave radiation.
visible radiation.
ultraviolet radiation.
14. Which of the following uses a grazing incidence telescope?
International Space Observatory.
International Space Station.
International Ultraviolet Explorer.
Chandra X-ray satellite.
15. The angle through which a ray of light is bent by a glass prism depends on the
brightness of the light.
photoelectric effect.
reflectivity of the prism.
wavelength of the light.
16. The focal length of an ideal mirror depends on
brightness of the light.
photoelectric effect.
wavelength of the light.
reflectivity of the prism.
17. Light can be described as having a “dual†nature. What does this mean?
Light can be expressed as brightness and colour.
Light behaves like a wave and like a particle.
Light goes slow and fast.
If light moves in one direction, then it moves in the opposite direction also.
18. What is the angular size of the Moon?
0.5 arcminutes
5 degrees
0.5 degrees
0.5 arcseconds
19. Which of the following space-based telescopes detected water in the Orion nebula?
Chandra
The International Space Observatory (ISO)
The International Ultraviolet Explorer (IUE)
Hubble
20. If the width of the objective of a telescope is doubled, what happens to its light gathering power?
The light gathering power remains the same.
The light gathering power increased by a factor of four.
The light gathering power is decreased by a factor of four.
The light gathering power is increased by a factor of two.
21. For a telescope the objective focal length is 80 cm and the eyepiece focal length is 2 cm, what is the magnification?
40
160
78
less than 1
22. To detect dim objects a telescope needs
a long tube.
high resolution.
large diameter.
high magnification.
23. A Charge Coupled Device is used in telescopes to
reduce the effect of segmentation of mirrors.
improve light gathering.
detect light.
compensate for sagging of the mirror.
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