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Copper has 8.0xx 10^(28) electrons per c...

Copper has 8.0`xx 10^(28)` electrons per cuble meter carrying a current and lying at right angle to a magnetic field of strength `5 xx 10^(-3)` T. experiences a force of `8.0 xx 10^(-2)` N. Calculate the drift velocity of free electrons in the wire.

Text Solution

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n = 8 `xx 10^(28) m^(-3) , l = 1m `
A = 8 `xx 10^(-6) m^(-2) , e = 1.6 xx 10^(-9)` C
Total charge contained in the wire
q = volume of wire `xx `ne = alne = `8 xx 10^(-6) xx 1 xx 8 xx 10^(28) xx 1.6 xx 10^(19)`C
`= 102.4 xx 10^(3)` C
If `v_(d) ` is the drift speed of electrons, then
F = `qv_(d) B sin 90^(@) = qv_(d) B `
`therefore v_(d) = (F)/(qB) = (8.0 xx 10^(-2))/(102.4 xx 10^(3) xx 5 xx 10^(-3) ) ms^(-1)`
`v_(d) = 1.56 xx 10^(-4) ms^(-1)`
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