{"id":84651,"date":"2025-06-01T02:43:21","date_gmt":"2025-06-01T02:43:21","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84651"},"modified":"2025-06-01T02:43:21","modified_gmt":"2025-06-01T02:43:21","slug":"a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/","title":{"rendered":"A photon of X-ray has energy of 1 keV. A photon of visible radiation h"},"content":{"rendered":"

A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?<\/p>\n

[amp_mcq option1=”The wavelength of X-ray photon is less than the wavelength of visible radiation photon.” option2=”Both the photons have different energies.” option3=”The speeds of both the photons in vacuum are different.” option4=”The frequency of X-ray photon is higher than the frequency of visible radiation photon.” correct=”option3″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2017<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck’s constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength.
\n<\/section>\n
\n– The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV).
\n– Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct.\n- Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct.\n- Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect.\n- Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.
\n<\/section>\n
\nElectromagnetic radiation spans a wide spectrum of frequencies and wavelengths, each with corresponding energy levels. While energy, frequency, and wavelength vary, the speed of propagation in a vacuum remains constant for all parts of the spectrum.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct? [amp_mcq option1=”The wavelength of X-ray photon is less than the wavelength of visible radiation photon.” option2=”Both the photons have different energies.” option3=”The speeds of … <\/p>\n

Detailed SolutionA photon of X-ray has energy of 1 keV. A photon of visible radiation h<\/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":[1101,1153,1128],"class_list":["post-84651","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1101","tag-optics","tag-physics","no-featured-image-padding"],"yoast_head":"\nA photon of X-ray has energy of 1 keV. A photon of visible radiation h<\/title>\n<meta name=\"description\" content=\"The energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck's constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength. - The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV). - Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.\" \/>\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-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A photon of X-ray has energy of 1 keV. A photon of visible radiation h\" \/>\n<meta property=\"og:description\" content=\"The energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck's constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength. - The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV). - Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T02:43:21+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=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"A photon of X-ray has energy of 1 keV. A photon of visible radiation h","description":"The energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck's constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength. - The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV). - Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.","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-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/","og_locale":"en_US","og_type":"article","og_title":"A photon of X-ray has energy of 1 keV. A photon of visible radiation h","og_description":"The energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck's constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength. - The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV). - Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T02:43:21+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/","url":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/","name":"A photon of X-ray has energy of 1 keV. A photon of visible radiation h","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T02:43:21+00:00","dateModified":"2025-06-01T02:43:21+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The energy (E), frequency (f), and wavelength (\u03bb) of a photon are related by the equations E = hf and E = hc\/\u03bb, where h is Planck's constant and c is the speed of light in vacuum. The speed of light in vacuum (c) is a universal constant, approximately 3 x 10\u2078 m\/s, and is the same for all electromagnetic radiations regardless of their energy, frequency, or wavelength. - The energy of the X-ray photon (1 keV = 1000 eV) is significantly higher than the energy of the visible radiation photon (3 eV). - Statement A: Since E = hc\/\u03bb, higher energy means shorter wavelength. E(X-ray) > E(Visible), so \u03bb(X-ray) < \u03bb(Visible). This statement is correct. - Statement B: The energies (1000 eV and 3 eV) are clearly different. This statement is correct. - Statement C: The speed of all electromagnetic radiation (including photons of X-rays and visible light) in vacuum is the constant 'c'. Their speeds in vacuum are the same, not different. This statement is incorrect. - Statement D: Since E = hf, higher energy means higher frequency. E(X-ray) > E(Visible), so f(X-ray) > f(Visible). This statement is correct.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/a-photon-of-x-ray-has-energy-of-1-kev-a-photon-of-visible-radiation-h\/#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 photon of X-ray has energy of 1 keV. A photon of visible radiation h"}]},{"@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\/84651","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=84651"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/84651\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=84651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=84651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=84651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}