31/10/2019
HOME EXERCÍCIOS DE FÍSICA EXERCÍCIOS SOBRE INDUÇÃO ELETROMAGNÉTICAEXERCÍCIOS SOBRE INDUÇÃO ELETROMAGNÉTICAEXERCÍCIOS DE FÍSICA
Indução eletromagnética é o fenômeno que origina a produção de uma força eletromotriz quando uma espira é colocada em um campo magnético variável.
Por Domiciano Correa Marques da Silva
Questão 1
Suponha que uma espira retangular de área igual a 2,4 x 10-1 m2 imersa em uma região onde existe um campo de indução magnética B, cuja intensidade é igual a 3 x 10-2 T, perpendicular ao plano da espira. De acordo com as informações, determine o fluxo magnético através da espira.
a) Ф= 7,2 x 10-3 Wb
b) Ф = 2,7 x 10-3 Wb
c) Ф = 2,4 x 10-3 Wb
d) Ф = 2,7 x 10-5 Wb
e) Ф = 7,2 x 10-5 Wb
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Questão 2
Determine o valor da tensão elétrica induzida entre as extremidades de um fio condutor de 60 cm de comprimento que se move com velocidade constante de 40 m/s perpendicularmente às linhas de indução magnética de um campo de 12 T.
a) ε= 288 V
b) ε = 2,88 V
c) ε = 28,8 V
d) ε = 8,28 V
e) ε = 88,2 V
Ver Resposta
Questão 3
(UFMG) A corrente elétrica induzida em uma espira circular será:
a) nula, quando o fluxo magnético que atravessa a espira for constante
b) inversamente proporcional à variação do fluxo magnético com o tempo
c) no mesmo sentido da variação do fluxo magnético
d) tanto maior quanto maior for a resistência da espira
e) sempre a mesma, qualquer que seja a resistência da espira.
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Questão 4
Suponha que uma espira quadrada de lado igual a 2 cm seja colocada em um campo magnético uniforme cuja intensidade vale 2 T. Determine o fluxo magnético nessa espira quando ela for colocada perpendicularmente às linhas de campo magnético.
a) Ф= 2,0008 Wb
b) Ф= 3,0018 Wb
c) Ф= 0,0048 Wb
d) Ф= 0,0028 Wb
e) Ф= 0,0008 Wb
Ver Resposta
Resposta - Questão 1
A equação que nos fornece o cálculo do fluxo magnético é:
Φ=B.A.cosθ
Como θ = 0º, podemos dizer que o sentido de B coincide com o sentido do vetor normal à área da espira. Sendo assim, temos que o fluxo através da espira é:
Φ=3 .10-2 .2,4 .10-1.cos0o
Φ=7,2 .10-3 Wb
Alternativa A
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Resposta - Questão 2
Para determinar a tensão elétrica induzida nos terminais, isto é, nas extremidades de um fio condutor retilíneo, fazemos uso da seguinte equação:
ε=B .L .v
ε=12 .0,6 .40
ε=288 V
Alternativa A
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Resposta - Questão 3
A alternativa A diz que a corrente elétrica será nula se não houver variação do fluxo magnético que atravessa a espira. Sendo assim, de acordo com a lei de Faraday, se o fluxo magnético através da espira não variar com o passar do tempo, então, não haverá corrente elétrica induzida na espira. Portanto, a alternativa A está correta.
Alternativa A
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Resposta - Questão 4
Como a reta normal à espira não irá formar ângulo com as linhas de indução magnética, temos que θ = 0, e como cos 0º = 1, temos:
Φ=B.A.cosθ
A = 0,022 = 0,0004 m2
Φ=2 .0,0004 .cos 0o
Φ=2 .0,0004 .1 ⟹ Φ=0,0008 Wb
Alternativa E
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SIGA O BRASIL ESCOLA
