Q. No.A battery is charged at a potential of \(15\) V for \(8\) hours when the current flowing is \(10\) A. The battery on discharge supplies a current of \(5\) A for \(15\) hours. The mean terminal voltage during discharges is \(14\) V. The "Watt hour" efficiency of the battery is:
1. \(80\%\)
2. \(90\%\)
3. \(87.5\%\)
4. \(82.5\%\)
1. \(80\%\)
2. \(90\%\)
3. \(87.5\%\)
4. \(82.5\%\)
A \(5~\text A\) fuse wire can withstand a maximum power of \(1~\text W\) in a circuit. The resistance of the fuse wire is:
1. \(5~\Omega\)
2. \(0.04~\Omega\)
3. \(0.2~\Omega\)
4. \(0.4~\Omega\)
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. | \(4.8~\Omega\) |
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 \( 𝐴 _1\) and the other one has a square cross-section of area \(A_2.\) The ratio of \(𝐴 _1 / 𝐴 _2 \) is:
| 1. | \(1.5\) | 2. | \(1\) |
| 3. | \(0.8\) | 4. | \(2\) |
Twelve wires of equal resistance \(R\) are connected to form a cube. The effective resistance between two diagonal ends \(A\) and \(E\) will be:
| 1. | \(\dfrac{5 R}{6}\) | 2. | \(\dfrac{6 R}{5}\) |
| 3. | \(12 R\) | 4. | \(3 R\) |
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. \(2.25\times 10^{15}~\text{m}^2\text{V}^{-1}\text{s}^{-1}\)
For the given circuit, the value of the resistance in which the maximum heat is produced is:
1. \(2~\Omega\)
2. \(6~\Omega\)
3. \(4~\Omega\)
4. \(12~\Omega\)
A potential divider is used to give outputs of \(2~\text{V}\) and \(3~\text{V}\) from a \(5~\text{V}\) source, as shown in the figure.
| 1. | \({R}_1=1~\text{k} \Omega, {R}_2=1 ~\text{k} \Omega, {R}_3=2 ~\text{k} \Omega\) |
| 2. | \({R}_1=2 ~\text{k} \Omega, {R}_2=1~\text{k} \Omega, {R}_3=2~\text{k} \Omega\) |
| 3. | \({R}_1=1 ~\text{k} \Omega, {R}_2=2~ \text{k} \Omega, {R}_3=2~ \text{k} \Omega\) |
| 4. | \({R}_1=3~\text{k} \Omega, {R}_2=2~\text{k} \Omega, {R}_3=2~ \text{k} \Omega\) |
Two batteries, one of emf \(18~\text{V}\) and internal resistance \(2~\Omega\) and the other of emf \(12~\text V\) and internal resistance \(1~\Omega,\) are connected as shown. Reading of the voltmeter is:
(if a voltmeter is ideal)
1. \(14~\text V\)
2. \(15~\text V\)
3. \(18~\text V\)
4. \(30~\text V\)
Current through the \(2~\Omega\) resistance in the electrical network shown is:
| 1. | zero | 2. | \(1~\text A\) |
| 3. | \(3~\text A\) | 4. | \(5~\text A\) |
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