Question

A wire of length l tapers uniformely from end P to end Q with the diameter at P twice that at Q. A potential difference is applied across the ends of the wire. Which graph represents the variation with distance of the drift velocity v of the conduction electrons ?

• A.
• B.
• C.
• D.

Answer 1

Answer: (D)

Answer 2

For a current carrying conductor

AV = constant. \ v = $\frac { \mathrm { K } } { \mathrm { A } }$ = $\frac { \mathrm { K } } { \pi \mathrm { r } ^ { 2 } }$ \ v µ

Now at x = 0 radius = 2r₀ ; at x = l radius =r₀

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