If the potential difference across ends of a metallic wire is doubled, the drift velocity of charge carriers will become:
1. double 
2. half
3. four times
4. one-fourth 

Subtopic:  Current & Current Density |
 84%
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The current in a wire varies with time according to the relation \(i = (3+2t)~\text{A}\). The amount of charge passing a cross section of the wire in the time interval \(t=0\) to \(t = 4.0~\text{s}\)  would be: (where \(t\) is time in seconds)
1. \(28\) C 2. \(30.5\) C
3. \(8\) C 4. \(82\) C
Subtopic:  Current & Current Density |
 85%
From NCERT
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The current in a wire varies with time according to the equation \(I=(4+2t),\) where \(I\) is in ampere and \(t\) is in seconds. The quantity of charge which has passed through a cross-section of the wire during the time \(t=2\) s to \(t=6\) s will be:

1. \(60\) C  2. \(24\) C
3. \(48\) 4. \(30\) C

Subtopic:  Current & Current Density |
 83%
From NCERT
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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:  Current & Current Density |
 82%
From NCERT
NEET - 2020
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Drift velocity \(v_d\) varies with the intensity of electric field as per the relation:
1. \(v_{d} \propto E\)
2. \(v_{d} \propto \frac{1}{E}\)
3. \(v_{d}= \text{constant}\)
4. \(v_{d} \propto E^2\)

Subtopic:  Current & Current Density |
 78%
From NCERT
PMT - 1981
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The drift velocity of free electrons in a conductor is \(v\) when a current \(i\) is flowing in it. If both the radius and current are doubled, then the drift velocity will be:
1.  \(v\)
2. \(\frac{v}{2}\)
3. \(\frac{v}{4}\)
4. \(\frac{v}{8}\)

Subtopic:  Current & Current Density |
 72%
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When the potential difference applied in a conductor is doubled and also the length of the conductor is halved, the drift speed of electrons in the conductor will:
1. not change
2. be halved
3. be four times
4. be doubled
Subtopic:  Current & Current Density |
 66%
From NCERT
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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:  Current & Current Density |
 66%
From NCERT
NEET - 2022
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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:  Current & Current Density |
 59%
From NCERT
NEET - 2015
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A current passes through a wire of variable cross-section in steady-state as shown. Then incorrect statement is:

     

1. Current density increases in the direction of the current.
2. Potential increases in the direction of the current.
3. Electric field increases in the direction of the current.
4. Drift speed increases in the direction of the current.

Subtopic:  Current & Current Density |
 55%
From NCERT
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