Exploring the Cosmos - Class Test 2 - Mapping the Universe
1. Long Baseline Interferometry is a technique often used in radio astronomy to
image neutrinos.
remove the effect of Cerenkov radiation.
improve the resolution of objects.
reduce the effect of light pollution in urban skies.
2. Karl Jansky was the pioneer of
optical astronomy
infra-red astronomy.
radio astronomy.
UV astronomy.
3. The LIGO gravitational wave detectors
are currently under construction.
are bar detectors.
have arm lengths of 600 m.
have arm lengths of 4 km.
4. Cerenkov radiation is given off when
an electron recombines with an ionised atom
a particle is travelling slower than the speed of light in a medium
an electron is ionised from an atom
a particle is travelling faster than the speed of light in a medium
5. Why is the colour of the sun during sunset red?
The sun changes its colour in 24 h from blue to red and back to blue.
The scattering of blue light is stronger than red light.
The refraction of light is different. Blue light is more strongly refracted.
The diffraction of light is different. Blue light is more strongly diffracted.
6. Which of the following processes is responsible for the absorption of Infra-Red radiation?
Excitation of vibrational modes of molecules.
Breaking of the chemical bonds.
Infra-Red radiation is not absorbed.
Splitting of the atomic nuclei.
7. The ISO satellite is sensitive to
IR.
X-rays.
Gamma rays.
UV.
8. The objective of a telescope is
the adaptor between the telescope and the human eye.
the object under observation.
the reason why that telescope has been buil
the part of it which first converges the light.
9. As light passes from one medium to another, its direction of travel changes. What is the name of this effect?
Interference
Refraction
Diffraction
Dispersion
10. How does an infrared telescope make detections?
By monitoring the number of electrons released by incident photons.
By monitoring changes in temperature caused by incident photons.
By detecting oscillating electric signals generated by incident photons.
By directly detecting the number of incident photons.
11. Which of the following processes is responsible for absorption of infrared radiation by the atmosphere?
The breaking of chemical bonds in ozone.
Interaction of the radiation with the nuclei of atoms in the atmosphere.
Conduction in an upper part of the atmosphere.
The excitation of the vibrational modes of water vapour molecules.
12. The twinkling of the stars is due to
diffusion.
refraction.
scattering.
absorption.
13. A Charge Coupled Device is used in telescopes to
reduce the effect of segmentation of mirrors.
detect light.
compensate for sagging of the mirror.
improve light gathering.
14. The Spitzer satellite uses
a grazing incidence mirror
a Schmidt-Cassegrain design
a prime focus arrangement
a Cassegrain design
15. The ISO satellite is sensitive to
UV.
X-rays.
IR.
Gamma rays.
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