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