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A circular coil of wire consisting of 100 turns each of radius 9 cm carries a current of 0.4 A. The magnitude of the magnetic field at the centre of coil is `[ mu_(0) = 1256 xx 10^(-7)` Sl unit]A. `2.4 xx 10^(-11) T`B. `2.79 xx 10^(-5)T`C. `2.97 xx 10^(-4)T`D. `2.79 xx 10^(-3)T` |
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Answer» Correct Answer - C Given number of turns n= 100 radius of coil `r = 9 cm = 9 xx 10^(-2) m` and current flow in the coil , `I = 0.4A` The magnitude of the meagnetic filed at the centre of a coil of n turns is given by `B = (mu_(0)nl)/(2r) " "........(i)` Substituting given values in Eq.(i) we, get `rArr " " B = (1256 xx 10^(-7) xx 100 xx 0.4)/(2 xx 10^(-1) xx 9 xx 10^(-2))` ` = 2.97 xx 10^(-4)T ` |
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