{"id":89062,"date":"2025-06-01T07:28:39","date_gmt":"2025-06-01T07:28:39","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=89062"},"modified":"2025-06-01T07:28:39","modified_gmt":"2025-06-01T07:28:39","slug":"an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/","title":{"rendered":"An incandescent electric bulb converts 20% of its power consumption in"},"content":{"rendered":"

An incandescent electric bulb converts 20% of its power consumption into light, and the remaining power is dissipated as heat. The bulb’s filament has a resistance of 200 \u03a9 and 2 A current flows through it. If the bulb remains ON for 10 h and the rate of electricity charge is \u20b95\/unit, then which among the following is the correct amount for the money spent on producing light ?<\/p>\n

[amp_mcq option1=”\u20b95″ option2=”\u20b96″ option3=”\u20b97″ option4=”\u20b98″ correct=”option4″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC NDA-2 – 2024<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy.
\n<\/section>\n
\nPower consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW.
\nTotal energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh.
\nTotal cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940.
\nEnergy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh.
\nCost spent on producing light = E_light * Rate = 1.6 kWh * \u20b95\/kWh = \u20b98.
\n<\/section>\n
\nIncandescent bulbs are inefficient in converting electrical energy into visible light; a large portion of the energy is dissipated as heat, which is why the question specifies that only 20% is converted to light. The remaining 80% (1.6 kWh * 4 = 6.4 kWh) is dissipated as heat, costing \u20b932 (\u20b940 – \u20b98).
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

An incandescent electric bulb converts 20% of its power consumption into light, and the remaining power is dissipated as heat. The bulb’s filament has a resistance of 200 \u03a9 and 2 A current flows through it. If the bulb remains ON for 10 h and the rate of electricity charge is \u20b95\/unit, then which among … <\/p>\n

Detailed SolutionAn incandescent electric bulb converts 20% of its power consumption in<\/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":[1094],"tags":[1103,1201,1128],"class_list":["post-89062","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-2","tag-1103","tag-electric-current","tag-physics","no-featured-image-padding"],"yoast_head":"\nAn incandescent electric bulb converts 20% of its power consumption in<\/title>\n<meta name=\"description\" content=\"The power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy. Power consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh. Total cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940. Energy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh. Cost spent on producing light = E_light * Rate = 1.6 kWh * \u20b95\/kWh = \u20b98.\" \/>\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\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"An incandescent electric bulb converts 20% of its power consumption in\" \/>\n<meta property=\"og:description\" content=\"The power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy. Power consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh. Total cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940. Energy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh. Cost spent on producing light = E_light * Rate = 1.6 kWh * \u20b95\/kWh = \u20b98.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:28:39+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":"An incandescent electric bulb converts 20% of its power consumption in","description":"The power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy. Power consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh. Total cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940. Energy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh. Cost spent on producing light = E_light * Rate = 1.6 kWh * \u20b95\/kWh = \u20b98.","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\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/","og_locale":"en_US","og_type":"article","og_title":"An incandescent electric bulb converts 20% of its power consumption in","og_description":"The power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy. Power consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh. Total cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940. Energy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh. Cost spent on producing light = E_light * Rate = 1.6 kWh * \u20b95\/kWh = \u20b98.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T07:28:39+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\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/","url":"https:\/\/exam.pscnotes.com\/mcq\/an-incandescent-electric-bulb-converts-20-of-its-power-consumption-in\/","name":"An incandescent electric bulb converts 20% of its power consumption in","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T07:28:39+00:00","dateModified":"2025-06-01T07:28:39+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The power consumed by the incandescent bulb is calculated using the given resistance and current. The total energy consumed over 10 hours is then calculated. Since only 20% of the power (and thus energy) is converted into light, the energy spent on producing light is 20% of the total energy consumed. The cost is calculated based on the rate per unit (kWh) for this amount of energy. Power consumed (P) = I\u00b2R = (2 A)\u00b2 * 200 \u03a9 = 4 * 200 = 800 W = 0.8 kW. Total energy consumed (E_total) = Power * Time = 0.8 kW * 10 h = 8 kWh. Total cost of electricity = E_total * Rate = 8 kWh * \u20b95\/kWh = \u20b940. Energy converted into light (E_light) = 20% of E_total = 0.20 * 8 kWh = 1.6 kWh. 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