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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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%
From NCERT
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The current in a wire varies with time according to the relation i= (3+2t) A. The amount of charge passing a cross section of the wire in the time interval t=0 to t=4.0 sec 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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A charged particle having drift velocity of \(7.5\times10^{-4}~\mathrm{ms^{-1}}\) in an electric field of \(3\times10^{-10}\) Vm-1, has mobility in m2V-1s-1 of:
1. 2.5×106
2. 2.5×10-6
3. 2.25×10-15
4. 2.25×1015

Subtopic:  Current & Current Density |
 81%
From NCERT
NEET - 2020
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Drift velocity vd varies with the intensity of electric field as per the relation: 

1. vdE

2. vd1E

3. vd = constant

4. vdE2 

Subtopic:  Current & Current Density |
 77%
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 |
 73%
From NCERT
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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 |
 56%
From NCERT
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If a metallic block has no potential difference applied across it, then the mean velocity of free electron is:
(T = absolute temperature of the block)

1. proportional to T. 2. proportional to\(\sqrt{\mathrm{T}} \)
3. zero. 4. finite but independent of temperature.
Subtopic:  Current & Current Density |
 51%
From NCERT
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Which of the following graph correctly represents the variation of mobility μ of electrons with applied electric field (E) in a metallic conductor?

1. 2.
3. 4.
Subtopic:  Current & Current Density |
From NCERT
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