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