Time
Distance
Time period
Light intensity
The billions of stars and other heavenly bodies in the universe are separated by such a large distances, so the ordinary units for measuring distances on earth i.e. metres, kilometers or miles are not adequate for the purpose.
For measuring these extremely large distances, we use two astronomical units, the light year and the parsec.
A light year is defined as the distance travelled by light in one year. Light-year is the unit of length to measure large distances (astronomical distances). The total distance travelled by light in a year is called 1 light year.
The speed of light is 300,000 km/s and 1 year has 1 × 365 × 24 × 60 × 60 seconds.
∴ 1 Light year = 300.000 × 365 × 24 × 60 × 60 km
1 Light year = 9.46 × 1012 km.
Another unit commonly used for measuring astronomical distances is the parsec.
1 parsec is equal to 3.26 light years.
The distance travelled by the light at a speed of 300,000 km/s in one minute (60 seconds) is called a light minute.
1 light minute = 300,000 km/s × 1 minute = 300,000 km/s × 60 sec = 18,000,000 km = 18 × 106 km.
Related MCQs
- The SYNONYM of the word \"PREMISE\" is? (CSS 1989 English Precis & Composition Paper)
- Outline
- Disbelieve
- Assumption
- Commitment
Submitted by: CSS Exam Desk Team
- Pakistan People’s Party was founded in? (CSS 2014 Current Affairs Paper)
- November 30, 1968
- November 30, 1967
- November 30, 1969
- None of these
Submitted by: CSS Exam Desk Team
- The SYNONYM of the word \"STENTORIAN\" is? (CSS 2016 English Precis & Composition Paper)
- Loud
- Violent
- Stealthy
- Misbegotten
Submitted by: CSS Exam Desk Team
- Who is the author of \"Hunter par Hunter\"? (CSS 2009 Pakistan Affairs Paper)
- Deputy Nazir Ahmed
- Sir syed Ahmed Khan
- Maulana Zafar Ali khan
- None of these
Submitted by: None of these
- Objectives Resolution was presented by? (CSS 2017 Current Affairs Paper)
- Mian Muhammad iftikharuddin
- Liaquat Ali khan
- Shabir Ahmed usmani
- None of these
Submitted by: CSS Exam Desk Team
- “The Reconstruction of Religious Thought” written by? (CSS 2016 Current Affairs Paper)
- Ahmed Ali
- Allama Muhammad Iqbal
- Javed Majeed
- None of these
Submitted by: CSS Exam Desk Team
- Who was the founder of republican party of USA? (CSS 2012 Current Affairs Paper)
- Alexander Hamilton
- Franklin Roosevelt
- George Washington
- None of these
Submitted by: CSS Exam Desk Team
- Night vision is possible with the help of? (CSS 2010 General Science & Ability Paper)
- Red light
- Violet light
- Infrared light
- Ultraviolet light
Submitted by: CSS Exam Desk Team
- Hajj was made obligatory in which Hijri? (CSS 2020 Islamic Studies Paper)
- 10th Hijri
- 9th Hijri
- 8th Hijri
- 7th Hijri
Submitted by: CSS Exam Desk Team
- The first constructed barrage of Pakistan is?(CSS 2012 Current Affairs Paper)
- Jinnah barrage
- Sukkur barrage
- Tunsa barrage
- None of these
Submitted by: CSS Exam Desk Team
- The _________ reply of my sister conveyed the clear message that she was not happy with me. (CCE 2023 Screening Test, December 1, 2024)
- Vivacious
- Sinuous
- Gentle
- Terse
Submitted by: CSS Exam Desk Team
- Which of the following cannot be considered As the renewable source of energy? (CSS 2022 General Science & Ability Paper)
- Petroleum
- Wind
- Solar
- None of these
Submitted by: CSS Exam Desk Team
- The Axis powers in World War II did not include? (CSS 2013 Current Affairs Paper)
- Germany
- the Soviet Union
- Italy
- Japan
Submitted by: CSS Exam Desk Team
- The average air pressure at sea level is? (CSS 2012 General Science & Ability Paper)
- 201.225 kilopascals (kPa)
- 101.325 kilopascals (kPa)
- 103.525 kilopascals (kPa)
- None of these options
Submitted by: CSS Exam Desk Team
- International Day for the Elimination of Violence against Women is observed annually on? (CSS 2013 Current Affairs Paper)
- 25th December
- 23rd November
- 25th November
- None of these
Submitted by: CSS Exam Desk Team
- Nelson Mandela International Day (or Mandela Day) is celebrated each year on? (CSS 2016 Current Affairs Paper)
- 18 June
- 18 July
- 18 August
- None of these
Submitted by: CSS Exam Desk Team
- One of the following countries produces maximum energy from atomic reactors? (CSS 2013 General Science & Ability Paper)
- France
- United States
- United Kingdom
- None of these options
Submitted by: CSS Exam Desk Team
- Since January 2019 how many times legislative elections have been held in Israel? (CSS 2021 Current Affairs Paper)
- One
- Two
- Three
- None of these
Submitted by: CSS Exam Desk Team
- Which of the following is non-sedimentary rock? (CSS 2020 General Science & Ability Paper)
- Limestone
- Sandstone
- Granite
- None of these
Submitted by: CSS Exam Desk Team
- Who accepted Akbar\'s \"Din-e-Illahi\"? (CSS 2009 Pakistan Affairs Paper)
- Todar Mal
- Ma\'an Singh
- Birbal
- None of these
Submitted by: CSS Exam Desk Team
- Sahara desert is located? (CSS 2014 Current Affairs Paper)
- Northern Africa
- Central Africa
- South America
- None of these
Submitted by: CSS Exam Desk Team
- ) If carbon dioxide is passed through lime water for a long time, the cloudy white color (initially formed) disappears because of the formation of? (CSS 2014 General Science & Ability Paper)
- Calcium bicarbonate
- Calcium hydroxide
- Calcium carbonate
- Calcium sulphate
Submitted by: CSS Exam Desk Team
- The study of the relationship between environment and organism is? (CCE 2023 Screening Test, December 1, 2024)
- Gerontology
- Ecology
- Lithography
- Entomology
Submitted by: CSS Exam Desk Team
- The height of the world\'s tallest building Burj Khalifa is? (CSS 2022 Current Affairs Paper)
- 848 meters
- 838 meters
- 828 meters
- None of the above.
Submitted by: CSS Exam Desk Team
- Operation Zarb-e-Azab was launched on? (CSS 2019 Current Affairs Paper)
- 24 April 2014
- 29 April 2014
- 15 June 2014
- None of these
Submitted by: CSS Exam Desk Team