{"id":231985,"date":"2025-06-11T15:28:52","date_gmt":"2025-06-11T15:28:52","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=231985"},"modified":"2025-06-11T15:28:54","modified_gmt":"2025-06-11T15:28:54","slug":"the-distance-travelled-by-light-year","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/11\/the-distance-travelled-by-light-year\/","title":{"rendered":"The distance travelled by light year."},"content":{"rendered":"\n

The distance travelled by light year. 1 light year = 9.46 \u00d7 10
m Q. 2.10. How many light years are there in one metre? (H.P.S.S.C.E. 2006 S) Ans. Now, 1 light year = 3 \u00d7 10
m s
\u00d7 (365 \u00d7 24 \u00d7 60 \u00d7 60) s = 9.46 \u00d7 10
m 1 m = \\frac{1}{9.46 \u00d7 10
= 1.057 \u00d7 10
light year Q. 2.11. Define astronomical unit. (H.P.S.S.C.E. 2006 S) distance of the sun from the earth.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Q.2.10. How many light years are there in one metre?<\/strong><\/h3>\n\n\n\n

(H.P.S.S.C.E. 2006 S)<\/em><\/p>\n\n\n\n

Answer:<\/strong><\/p>\n\n\n\n

We know:
1 light year<\/strong> is the distance that light travels in one year<\/strong>.
Speed of light, c = 3 \u00d7 10\u2078 m\/s<\/strong>
Time in one year = 365 \u00d7 24 \u00d7 60 \u00d7 60 = 31,536,000 seconds<\/strong><\/p>\n\n\n\n

So,
1 light year<\/strong> = 3 \u00d7 10\u2078 m\/s \u00d7 31,536,000 s
= 9.46 \u00d7 10\u00b9\u2075 metres<\/strong><\/p>\n\n\n\n

Now,
To find how many light years are in 1 metre<\/strong>:1 metre=19.46\u00d71015 light years1 \\text{ metre} = \\frac{1}{9.46 \\times 10^{15}} \\text{ light years}1 metre=9.46\u00d710151\u200b light years<\/p>\n\n\n\n

= 1.057 \u00d7 10\u207b\u00b9\u2076 light years<\/strong><\/p>\n\n\n\n

\n\n\n\n

Q.2.11. Define Astronomical Unit (AU).<\/strong><\/h3>\n\n\n\n

(H.P.S.S.C.E. 2006 S)<\/em><\/p>\n\n\n\n

Answer:<\/strong>
An astronomical unit (AU)<\/strong> is the average distance between the Earth and the Sun.
1 AU = 1.496 \u00d7 10\u00b9\u00b9 metres<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation<\/strong><\/h3>\n\n\n\n

In astronomy, very large distances are involved, making it impractical to use regular units like metres or kilometres. Instead, scientists use specialized units such as the light year<\/strong> and the astronomical unit (AU)<\/strong> to express these vast measurements.<\/p>\n\n\n\n

A light year<\/strong> is the distance light travels in one year in a vacuum. Since light moves at an astonishing speed of 3 \u00d7 10\u2078 metres per second<\/strong>, and there are 31,536,000 seconds<\/strong> in a year, the total distance light covers in a year is:Distance=speed\u00d7time=3\u00d7108\u00d731,536,000=9.46\u00d71015 metres\\text{Distance} = \\text{speed} \u00d7 \\text{time} = 3 \u00d7 10\u2078 \u00d7 31,536,000 = 9.46 \u00d7 10^{15} \\text{ metres}Distance=speed\u00d7time=3\u00d7108\u00d731,536,000=9.46\u00d71015 metres<\/p>\n\n\n\n

This is a huge number, which makes the light year a convenient unit for expressing distances between stars and galaxies.<\/p>\n\n\n\n

Conversely, if we wish to express 1 metre<\/strong> in terms of light years, we take the reciprocal:1 metre=19.46\u00d71015=1.057\u00d710\u221216 light years1 \\text{ metre} = \\frac{1}{9.46 \u00d7 10^{15}} = 1.057 \u00d7 10^{-16} \\text{ light years}1 metre=9.46\u00d710151\u200b=1.057\u00d710\u221216 light years<\/p>\n\n\n\n

This value is extremely small, showing how vast a single light year really is.<\/p>\n\n\n\n

Another important unit is the Astronomical Unit (AU)<\/strong>. It is defined as the average distance from the Earth to the Sun<\/strong>, which is about 1.496 \u00d7 10\u00b9\u00b9 metres<\/strong>. This unit is especially useful for measuring distances within our solar system.<\/p>\n\n\n\n

By using units like the light year and AU, astronomers can communicate enormous distances more efficiently and clearly in their observations and research.<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

The distance travelled by light year. 1 light year = 9.46 \u00d7 10m Q. 2.10. How many light years are there in one metre? (H.P.S.S.C.E. 2006 S) Ans. Now, 1 light year = 3 \u00d7 10m s\u00d7 (365 \u00d7 24 \u00d7 60 \u00d7 60) s = 9.46 \u00d7 10m 1 m = \\frac{1}{9.46 \u00d7 10= […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-231985","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/231985","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=231985"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/231985\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=231985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=231985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=231985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}