MCQ
A $3\,^oC$ rise in temperature is observed in a conductor by passing a certain current. When the current is doubled, the rise in temperature will be ............. $^oC$
  • A
    $15$
  • $12$
  • C
    $9$
  • D
    $3$

Answer

Correct option: B.
$12$
b
${i^2}Rt = C\theta = 3\,C;$     $C =$ Thermal  capacity

when ${i_1} = 2i  \Rightarrow  C{\theta _1} = 4{i^2}Rt = 4 \times 3\,C \Rightarrow {\theta _1} = 12\,^oC$

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