Question

The magnetic induction at a point P which is at a distance of 2 cm from a long current-carrying wire is 10^-6 T. The induction at a distance 8 cm from same current-carrying wire is ______.

विकल्प

• 2.5 x 10^-7 T

• 2.5 x 10^-9 T

• 2.5 x 10^-3 T

• 2.5 x 10⁷ T

Answer 1

The magnetic induction at a point P which is at a distance of 2 cm from a long current-carrying wire is 10^-6 T. The induction at a distance 8 cm from same current-carrying wire is 2.5 x 10^-7 T.

Explanation:

`"B" (µ_0 "I")/(2pi"r")`

∴ `"B"  alpha 1/"R"`

`"B"_1/"B"_2 = "R"_2/("R"_1`

∴  `10_-6/"B"_2 = 8/2`

∴  `"B"_2 = 2.5 xx 10^-7"T"`