Physics - Current Electricity Question with Solution | TestHub

PhysicsCurrent ElectricityMicroscopicMedium2 minQB

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Passage / Comprehension

A small caterpillar crawls in the direction of electron drift along bare copper wire that carries a current of 2.56 A . It travels with the drift speed of the electron in the wire of uniform cross section area $1 mm^{2}$ . Number of free electrons for copper $= 8 \times 1 0^{22} / cc$ & resistivity of copper $= 1.6 \times 1 0^{- 8} Ω m$ .

How much time would the caterpillar take to crawl 1.0 cm?

Options:

Answer:

Solution:

$J = \frac{I}{A}; J = N e v_{d}$

$v_{d} = \frac{I}{A N e} = \frac{2.56}{1 0 ^{- 6} \times 8 \times 1 0 ^{28} \times 1.6 \times 1 0 ^{- 19}}$

$= 2 \times 1 0^{- 4}$ m/s

Hence $t = \frac{1 0 ^{- 2}}{2 \times 1 0 ^{- 4}} = 50$ sec.

Stream:JEESubject:PhysicsTopic:Current ElectricitySubtopic:Microscopic

⏱ 2mℹ️ Source: QB

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