{"id":84559,"date":"2025-06-01T02:37:29","date_gmt":"2025-06-01T02:37:29","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84559"},"modified":"2025-06-01T02:37:29","modified_gmt":"2025-06-01T02:37:29","slug":"a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/","title":{"rendered":"A person rings a metallic bell near a strong concrete wall. He hears t"},"content":{"rendered":"

A person rings a metallic bell near a strong concrete wall. He hears the echo after 0.3 s. If the sound moves with a speed of 340 m\/s, how far is the wall from him?<\/p>\n

[amp_mcq option1=”102 m” option2=”11 m” option3=”51 m” option4=”30 m” correct=”option3″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2016<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
The sound travels from the person to the wall and then reflects back to the person as an echo. The total distance covered by the sound is twice the distance between the person and the wall. The time taken for this round trip is 0.3 seconds, and the speed of sound is 340 m\/s.
\nTotal distance = Speed \u00d7 Time
\nTotal distance = 340 m\/s \u00d7 0.3 s = 102 meters.
\nThe distance to the wall is half of the total distance.
\nDistance to wall = Total distance \/ 2 = 102 m \/ 2 = 51 meters.<\/section>\n
An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.<\/section>\n
The speed of sound in air is approximately 343 m\/s at 20\u00b0C, but it varies with temperature and humidity. The value 340 m\/s used in the problem is a typical approximation.<\/section>\n","protected":false},"excerpt":{"rendered":"

A person rings a metallic bell near a strong concrete wall. He hears the echo after 0.3 s. If the sound moves with a speed of 340 m\/s, how far is the wall from him? [amp_mcq option1=”102 m” option2=”11 m” option3=”51 m” option4=”30 m” correct=”option3″] This question was previously asked in UPSC CDS-1 – 2016 … <\/p>\n

Detailed SolutionA person rings a metallic bell near a strong concrete wall. He hears t<\/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":[1098,1128,1147],"class_list":["post-84559","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1098","tag-physics","tag-sound","no-featured-image-padding"],"yoast_head":"\nA person rings a metallic bell near a strong concrete wall. He hears t<\/title>\n<meta name=\"description\" content=\"The sound travels from the person to the wall and then reflects back to the person as an echo. The total distance covered by the sound is twice the distance between the person and the wall. The time taken for this round trip is 0.3 seconds, and the speed of sound is 340 m\/s. Total distance = Speed \u00d7 Time Total distance = 340 m\/s \u00d7 0.3 s = 102 meters. The distance to the wall is half of the total distance. Distance to wall = Total distance \/ 2 = 102 m \/ 2 = 51 meters. An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.\" \/>\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-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A person rings a metallic bell near a strong concrete wall. He hears t\" \/>\n<meta property=\"og:description\" content=\"The sound travels from the person to the wall and then reflects back to the person as an echo. The total distance covered by the sound is twice the distance between the person and the wall. The time taken for this round trip is 0.3 seconds, and the speed of sound is 340 m\/s. Total distance = Speed \u00d7 Time Total distance = 340 m\/s \u00d7 0.3 s = 102 meters. The distance to the wall is half of the total distance. Distance to wall = Total distance \/ 2 = 102 m \/ 2 = 51 meters. An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T02:37:29+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 rings a metallic bell near a strong concrete wall. 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An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.","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-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/","og_locale":"en_US","og_type":"article","og_title":"A person rings a metallic bell near a strong concrete wall. He hears t","og_description":"The sound travels from the person to the wall and then reflects back to the person as an echo. The total distance covered by the sound is twice the distance between the person and the wall. The time taken for this round trip is 0.3 seconds, and the speed of sound is 340 m\/s. Total distance = Speed \u00d7 Time Total distance = 340 m\/s \u00d7 0.3 s = 102 meters. The distance to the wall is half of the total distance. Distance to wall = Total distance \/ 2 = 102 m \/ 2 = 51 meters. An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T02:37:29+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-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/","url":"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/","name":"A person rings a metallic bell near a strong concrete wall. 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An echo involves sound travelling to a surface and back, so the distance to the surface is half the total distance covered by the sound.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/a-person-rings-a-metallic-bell-near-a-strong-concrete-wall-he-hears-t\/#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 rings a metallic bell near a strong concrete wall. 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