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Fuse - class-XII
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Three fuse wires A, B and C tinned copper having identical cross section and length 8 cm, 12 cm and 16 cm are used as fuses. For the same value of current
AnswerClick to flip back
A
all fuse will melt for same current
💡 Explanation:
Heat lost per second per unit surface area of fuse wire is
$H = \dfrac{I^2 \rho }{2 \pi ^2 r^3}$
$\Rightarrow I^2 \propto r^3$
$\Rightarrow I \propto r^{\dfrac{3}{2}}$
Hence, all fuse will melt for same current as they are independent of length of fuse wire.