{"id":85337,"date":"2025-06-01T03:12:37","date_gmt":"2025-06-01T03:12:37","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=85337"},"modified":"2025-06-01T03:12:37","modified_gmt":"2025-06-01T03:12:37","slug":"a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/","title":{"rendered":"A person burned a firecracker in front of a cliff and heard its echo 5"},"content":{"rendered":"

A person burned a firecracker in front of a cliff and heard its echo 5 s after it burst. The distance of the cliff from the person, if the speed of the sound is 340 m\/s, is close to<\/p>\n

[amp_mcq option1=”1700 m” option2=”170 m” option3=”85 m” option4=”850 m” correct=”option4″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2023<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m.
\n<\/section>\n
\nThe total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.
\n<\/section>\n
\nEcho is the reflection of sound waves from a surface. The time delay between the original sound and the echo is used to determine the distance of the reflecting surface. This principle is used in sonar and ultrasound imaging.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

A person burned a firecracker in front of a cliff and heard its echo 5 s after it burst. The distance of the cliff from the person, if the speed of the sound is 340 m\/s, is close to [amp_mcq option1=”1700 m” option2=”170 m” option3=”85 m” option4=”850 m” correct=”option4″] This question was previously asked in … <\/p>\n

Detailed SolutionA person burned a firecracker in front of a cliff and heard its echo 5<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1087],"tags":[1105,1128,1147],"class_list":["post-85337","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1105","tag-physics","tag-sound","no-featured-image-padding"],"yoast_head":"\nA person burned a firecracker in front of a cliff and heard its echo 5<\/title>\n<meta name=\"description\" content=\"The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m. The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A person burned a firecracker in front of a cliff and heard its echo 5\" \/>\n<meta property=\"og:description\" content=\"The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m. The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:12:37+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"A person burned a firecracker in front of a cliff and heard its echo 5","description":"The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m. The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/","og_locale":"en_US","og_type":"article","og_title":"A person burned a firecracker in front of a cliff and heard its echo 5","og_description":"The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m. The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:12:37+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/","url":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/","name":"A person burned a firecracker in front of a cliff and heard its echo 5","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:12:37+00:00","dateModified":"2025-06-01T03:12:37+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m\/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v \u00d7 t = 340 m\/s \u00d7 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total \/ 2 = 1700 m \/ 2 = 850 m. The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed \u00d7 Time.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/a-person-burned-a-firecracker-in-front-of-a-cliff-and-heard-its-echo-5\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CDS-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cds-1\/"},{"@type":"ListItem","position":3,"name":"A person burned a firecracker in front of a cliff and heard its echo 5"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/85337","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=85337"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/85337\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=85337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=85337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=85337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}