{"id":11339,"date":"2024-11-08T16:52:36","date_gmt":"2024-11-08T16:52:36","guid":{"rendered":"https:\/\/fisicaevestibular.com.br\/novo\/?page_id=11339"},"modified":"2024-12-03T13:07:42","modified_gmt":"2024-12-03T13:07:42","slug":"resistores-primeira-lei-de-ohm-en","status":"publish","type":"page","link":"https:\/\/fisicaevestibular.com.br\/novo\/eletricidade\/eletrodinamica\/resistores-primeira-lei-de-ohm-en\/","title":{"rendered":"Resistors \u2013 Ohm’s First Law EN"},"content":{"rendered":"

RESISTORS \u2013 OHM\u2019S FIRST LAW<\/span><\/h1>\n
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Resistors \u2013 Ohm\u2019s First Law \u2013 Electrical Power of a Resistor<\/span><\/b><\/p>\n

Joule effect<\/span><\/b><\/p>\n

\"\"\u00a0And\u00a0<\/span><\/b>as Joule does\u00a0<\/span><\/b>\u00a0 in a\u00a0<\/b>metallic conductor\u00a0<\/b>, the\u00a0<\/b>free electrons of the electric current,\u00a0<\/b>during their\u00a0<\/b>movements,\u00a0<\/b>continually suffer\u00a0<\/b>collisions\u00a0<\/b>with the\u00a0<\/b>atoms of the crystal lattice of this conductor,\u00a0<\/b>transferring\u00a0\u00a0<\/b>part\u00a0<\/b>of their\u00a0<\/b>kinetic energy to them and, as a result, the atoms of the conductor,\u00a0<\/b>as a whole, begin to\u00a0<\/b>vibrate with greater energy.<\/b><\/span>\u00a0\"\"<\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/p>\n

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This\u00a0<\/span><\/b>increase in the \u201cvibration level\u201d of the\u00a0<\/span><\/b>conductor\u2019s atoms\u00a0<\/span><\/b>causes an increase\u00a0<\/span><\/b>in its\u00a0<\/span><\/b>temperature,\u00a0<\/span><\/b>causing it to\u00a0<\/span><\/b>release thermal energy (heat).\u00a0<\/span><\/b>This phenomenon is called the Joule effect.<\/b><\/span><\/b><\/b><\/p>\n

Generators and receivers<\/span><\/b><\/p>\n

\"\"\u00a0\u00a0Generators\u00a0<\/span><\/b>In\u00a0<\/b>electrical circuits\u00a0<\/b>there are, in addition to other elements,\u00a0<\/b>generators whose function is to<\/b><\/span>\u00a0\"\"<\/b><\/b><\/b><\/b><\/b>transform any type of energy into electrical energy.\u00a0<\/span><\/b>Examples:\u00a0<\/span><\/b>batteries\u00a0<\/span><\/b>, in<\/span><\/b><\/p>\n

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which convert\u00a0<\/span><\/b>chemical energy into electrical energy.\u00a0<\/span><\/b>In\u00a0<\/span><\/b>hydroelectric plants,\u00a0<\/span><\/b>the mechanical energy of moving water is transformed\u00a0<\/span><\/b>into electrical energy, through generators, etc.<\/span><\/b><\/p>\n

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Resistors<\/span><\/b><\/p>\n

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\"\"\u00a0\u00a0One\u00a0<\/span><\/b>ohm (1\u03a9)\u00a0<\/span><\/b>is the\u00a0<\/span><\/b>value of electrical resistance\u00a0<\/span><\/b>between two points P and Q of a\u00a0<\/span><\/b>conductor\u00a0<\/span><\/b>when,\u00a0<\/span><\/b>under a potential difference of 1 volt (1V ), a\u00a0<\/span><\/b>constant electric current of 1 ampere (1A)\u00a0<\/b><\/span>flows through it .<\/span><\/b><\/b><\/p>\n

\"\"\u00a0\u00a0Symbolic representation of a resistor:<\/span><\/b><\/p>\n

\"\"<\/p>\n

\"\"<\/p>\n

The\u00a0<\/span><\/b>greater the slope of the line,\u00a0<\/span><\/b>the greater the angle, and therefore\u00a0<\/span><\/b>, the greater the resistance of the conductor (resistor).<\/span><\/b><\/p>\n

Electrical power of a resistive conductor (resistor)<\/span><\/b><\/p>\n

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What you should know, information and tips<\/span><\/b><\/p>\n

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We must note that the\u00a0<\/span><\/b>electrical resistance of the resistor depends only on the\u00a0<\/span><\/b>resistor\u00a0<\/span><\/b>and\u00a0<\/span><\/b>its\u00a0<\/span><\/b>temperature\u00a0<\/span><\/b>and that\u00a0<\/span><\/b>1\u00a0<\/span><\/b>W\u00a0<\/b>= 1 V.1 A.<\/b><\/span>\u00a0<\/b><\/b>\u00a0<\/b><\/b><\/p>\n

\"\"<\/p>\n

We\u00a0<\/span><\/b>often use multiples of the ohm\u00a0<\/span><\/b>1kW\u00a0<\/b>= 103\u00a0<\/b>W<\/b><\/sup>\u00a0and 1 MW\u00a0<\/b>=\u00a0<\/b>106<\/b><\/sup>\u00a0W.<\/b><\/span>\"\"\u00a0<\/b><\/b>\u00a0<\/b><\/b><\/b>\u00a0<\/b><\/sup><\/b>\u00a0<\/b><\/b><\/b>\u00a0<\/b><\/sup><\/b><\/p>\n

\"\"<\/p>\n

<\/b>Most\u00a0<\/span><\/b>metals are\u00a0<\/b><\/span>ohmic resistors\u00a0<\/span><\/b>when\u00a0<\/span><\/b>their temperatures are kept constant.<\/span><\/b><\/p>\n

because, the higher the temperature of these resistors,\u00a0<\/span><\/b>the greater the vibratory movement\u00a0<\/b>of their molecules and atoms,\u00a0<\/b>making it difficult for the electric current to pass through\u00a0<\/b>(movement of free electrons) and\u00a0<\/b>thus increasing their electrical resistance.<\/b><\/span><\/b><\/b><\/b><\/b><\/b><\/b><\/p>\n

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The\u00a0<\/span><\/b>electrical resistance of a conductor depends on the points\u00a0<\/span><\/b>where you are\u00a0<\/span><\/b>measuring the potential difference\u00a0<\/span><\/b>.\u00a0<\/b>Thus,\u00a0\u00a0<\/b>for the\u00a0<\/b>same voltage U\u00a0<\/b>,\u00a0<\/b>the\u00a0<\/b>greater the distance between the two points,\u00a0<\/b>the greater the value of the electrical resistance\u00a0<\/b>and consequently the lower the value of the\u00a0<\/b>electric\u00a0<\/b>current\u00a0<\/b>\u00a0i,\u00a0<\/b>since, in this case, in the\u00a0<\/b>expression R=U\/i,\u00a0<\/b>i\u00a0<\/b>is\u00a0<\/b>inversely proportional to R,\u00a0<\/b>with\u00a0<\/b>U remaining constant.<\/b><\/span>\u00a0<\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b>\u00a0<\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/b><\/p>\n

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 <\/p>\n

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Electric current\u00a0<\/span><\/b>always flows from the highest to the lowest potential, as there is\u00a0<\/span><\/b>\u201closs\u201d\u00a0<\/b><\/span>along the way\u00a0\u00a0<\/span><\/b>, that is,\u00a0<\/b>transformation of electrical energy into thermal energy (the \u201cJoule effect\u201d), leaving the final potential lower than the initial one.<\/b><\/span><\/b><\/b><\/b><\/p>\n

\"\"<\/p>\n

One ohm (1\u03a9)\u00a0<\/span><\/b>is the value of\u00a0<\/span><\/b>electrical resistance\u00a0<\/span><\/b>between two points P and Q of a conductor when,\u00a0<\/span><\/b>under a potential difference of 1 volt.<\/span><\/b><\/p>\n

\"\"<\/p>\n

<\/b>Superconductivity\u00a0<\/span><\/b>is the name given\u00a0<\/b><\/span>to the phenomenon by which the\u00a0<\/span><\/b>resistance of certain metals disappears\u00a0<\/span><\/b>at\u00a0<\/span><\/b>very low temperatures.<\/span><\/b><\/b><\/p>\n

<\/b>A conductor that has zero resistivity (proportion to resistance)\u00a0<\/b>is called a superconductor.<\/b><\/span><\/b><\/p>\n

The\u00a0<\/span><\/b>temperature\u00a0<\/span><\/b>at which a metal becomes\u00a0<\/span><\/b>a superconductor is close to absolute zero\u00a0<\/span><\/b>and varies from metal to metal.<\/span><\/b><\/p>\n

To date,\u00a0<\/span><\/b>few metals have demonstrated this phenomenon.\u00a0<\/span><\/b>Examples include mercury, which becomes a superconductor at 4.19 K; thorium, at 1.4 K; and lead, at 7.2 K.<\/b><\/span><\/b><\/b><\/p>\n

\"ohm's<\/p>\n

\"\"<\/p>\n

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An\u00a0<\/span><\/b>electric shower\u00a0<\/span><\/b>sometimes\u00a0<\/span><\/b>takes a while to start heating up,\u00a0<\/span><\/b>as the\u00a0<\/span><\/b>water pressure\u00a0<\/span><\/b>connects the electrical contacts through a diaphragm.<\/b><\/span><\/b><\/b><\/p>\n

\"\"<\/p>\n

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Check out the exercises with commented solutions<\/span><\/a><\/h3>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

RESISTORS \u2013 OHM\u2019S FIRST LAW Resistors \u2013 Ohm\u2019s First Law \u2013 Electrical Power of a Resistor Joule effect \u00a0And\u00a0as Joule does\u00a0\u00a0 in a\u00a0metallic conductor\u00a0, the\u00a0free electrons of the electric current,\u00a0during their\u00a0movements,\u00a0continually suffer\u00a0collisions\u00a0with the\u00a0atoms of the crystal lattice of this conductor,\u00a0transferring\u00a0\u00a0part\u00a0of their\u00a0kinetic energy to them and, as a result, the atoms of the conductor,\u00a0as a whole, begin to\u00a0vibrate with greater energy.\u00a0<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1676,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"class_list":["post-11339","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/11339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/comments?post=11339"}],"version-history":[{"count":2,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/11339\/revisions"}],"predecessor-version":[{"id":12016,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/11339\/revisions\/12016"}],"up":[{"embeddable":true,"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/pages\/1676"}],"wp:attachment":[{"href":"https:\/\/fisicaevestibular.com.br\/novo\/wp-json\/wp\/v2\/media?parent=11339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}