A copper wire of radius $$1$$ mm contains $$10^{22}$$ free electrons per cubic metre. The drift velocity for free electrons when $$10$$ A current flows through the wire will be:
(Given, charge on electron = $$1.6\times10^{-19}$$ C)
1. $$\dfrac{6.25\times10^4}{\pi}$$ m/s
2. $$\dfrac{6.25}{\pi}\times10^3$$ m/s
3. $$\dfrac{6.25}{\pi}$$ m/s
4. $$\dfrac{6.25\times10^5}{\pi}$$ m/s
Subtopic: Â Current & Current Density |
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From NCERT
NEET - 2023
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When no current is passed through a conductor,

 (a) the free electrons do not move. (b) the average speed of a free electron over a large period of time is zero. (c) the average velocity of a free electron over a large period of time is zero. (d) the average of the velocities of all the free electrons at an instant is zero.

Choose the correct option:

 1 (a) only 2 (b), (c) 3 (c), (d) 4 (a), (d)
Subtopic: Â Current & Current Density |
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Across a metallic conductor of non-uniform cross-section, a constant potential difference is applied. The quantity which remains constant along the conductor is:
 1 current density 2 current 3 drift velocity 4 electric field
Subtopic: Â Current & Current Density |
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From NCERT
NEET - 2015
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A copper wire of length $$10$$ m and radius $$\left({10^{-2}/\sqrt{\pi}}\right)$$ m has an electrical resistance of $$10~\Omega.$$ The current density in the wire for an electric field strength of $$10$$ (V/m) is:
1. $$10^{5}$$ A/m2
2. $$10^{4}$$ A/m2
3. $$10^{6}$$ A/m2
4. $$10^{-5}$$ A/m2
Subtopic: Â Current & Current Density |
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From NCERT
NEET - 2022
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A charged particle having drift velocity of $$7.5\times10^{-4}~\text{ms}^{-1}$$ in an electric field of $$3\times10^{-10}~\text{Vm}^{-1}$$, has mobility of:
1. $$2.5\times 10^{6}~\text{m}^2\text{V}^{-1}\text{s}^{-1}$$
2. $$2.5\times 10^{-6}~\text{m}^2\text{V}^{-1}\text{s}^{-1}$$
3. $$2.25\times 10^{-15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}$$
4. $$2.25\times 10^{15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}$$

Subtopic: Â Current & Current Density |
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From NCERT
NEET - 2020
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