Class 12 Physics · Chapter 9 · Test 1
Luminosity and Blackbody Radiation
43 MCQs
43 questions · 35 min · 43 marks
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Sample questions
The first 5 of 43. Try each one, then tap to see the answer.
Question 1
Space refers to the region:
- ABeyond Earth's atmosphere where celestial bodies exist and interact
- BOnly inside the atmosphere
- COnly under the oceans
- DOnly within the Sun
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Answer: A
Space is the region beyond Earth's atmosphere in which planets stars and galaxies exist and interact through gravity and radiation.
Question 2
The environment includes:
- AOnly living things
- BAir water land climate and ecosystems
- COnly the stars
- DOnly the oceans
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Answer: B
The environment is the surrounding physical chemical and biological conditions and includes air water land climate and ecosystems.
Question 3
Luminosity is defined as the:
- ABrightness of a star as seen from Earth
- BTotal power of radiation emitted by a star
- CTemperature of a star
- DDistance of a star
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Answer: B
Luminosity is the total energy emitted by a star per unit time as electromagnetic radiation.
Question 4
The SI unit of luminosity is the:
- AJoule
- BNewton
- CWatt
- DKelvin
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Answer: C
Luminosity is power so it is measured in watts.
Question 5
The luminosity of a star primarily depends on its:
- AMass and age only
- BRadius and surface temperature
- CDistance from Earth
- DColour of the sky
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Answer: B
Larger stars and hotter stars radiate more energy.
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