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. | \(48\) C | 4. | \(30\) C |
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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 of:
1.
2.
3.
4.
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Drift velocity vd varies with the intensity of electric field as per the relation:
1.
2.
3. vd = constant
4.
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The resistance of a wire is \(R\) ohm. If it is melted and stretched to \(n\) times its original length, its new resistance will be:
1. \(nR\)
2. \(\frac{R}{n}\)
3. \(n^2R\)
4. \(\frac{R}{n^2}\)
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Two solid conductors are made up of the same material and have the same length and the same resistance. One of them has a circular cross-section of area and the other one has a square cross-section of area . The ratio is:
1. | 1.5 | 2. | 1 |
3. | 0.8 | 4. | 2 |
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The dependence of resistivity \((\rho)\) on the temperature \((T)\) of a semiconductor is, roughly, represented by:
1. | 2. | ||
3. | 4. |
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The equivalent resistance between \(A\) and \(B\) for the mesh shown in the figure is:
1. \(7.2\) \(\Omega\)
2. \(16\) \(\Omega\)
3. \(30\) \(\Omega\)
4. \(4.8\) \(\Omega\)
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A potential divider is used to give outputs of 2 V and 3 V from a 5 V source, as shown in the figure.
Which combination of resistances, from the ones given below, give the correct voltages?
1. | \(\mathrm{R}_1=1 \mathrm{k} \Omega, \mathrm{R}_2=1 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
2. | \(\mathrm{R}_1=2 \mathrm{k} \Omega, \mathrm{R}_2=1 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
3. | \(\mathrm{R}_1=1 \mathrm{k} \Omega, \mathrm{R}_2=2 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
4. | \(\mathrm{R}_1=3 \mathrm{k} \Omega, \mathrm{R}_2=2 \mathrm{k} \Omega, \mathrm{R}_3=2 \mathrm{k} \Omega\) |
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In the circuit shown in the figure, the effective resistance between A and B is:
1. 2
2. 4
3. 6
4. 8
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The effective resistance between points P and Q of the electrical circuit shown in the figure is:
1.
2.
3.
4.
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