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 constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed doubles if:
| 1. | both the length and the radius of the wire are halved. |
| 2. | both the length and the radius of the wire are doubled. |
| 3. | the radius of the wire is doubled. |
| 4. | The length of the wire is doubled. |
| (a) | conservation of the current density vector. |
| (b) | conservation of charge. |
| (c) | the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction. |
| (d) | the fact that there is no accumulation of charges at a junction. |
Which of the above statements are correct?
| 1. | (b) and (c) |
| 2. | (a) and (c) |
| 3. | (b) and (d) |
| 4. | (c) and (d) |
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 circuit shown in the figure, the current \(I\) will be:

| 1. | \(0.75~\text{A}\) | 2. | \(1~\text{A}\) |
| 3. | \(1.5~\text{A}\) | 4. | \(0.5~\text{A}\) |
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. | \(2\) |
For the circuit given below, Kirchhoff's loop rule for the loop \(BCDEB\) is given by the equation:
| 1. | \(-{i}_2 {R}_2+{E}_2-{E}_3+{i}_3{R}_1=0\) |
| 2. | \({i}_2{R}_2+{E}_2-{E}_3-{i}_3 {R}_1=0\) |
| 3. | \({i}_2 {R}_2+{E}_2+{E}_3+{i}_3 {R}_1=0\) |
| 4. | \(-{i}_2 {R}_2+{E}_2+{E}_3+{i}_3{R}_1=0\) |
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. | \(4.8~\Omega\) |
When a \(100~\text{W},\) \(240~\text{V}\) bulb is operated at \(200~\text{volt},\) the current in it is:
1. \(0.35~\text{A}\)
2. \(0.42~\text{A}\)
3. \(0.50~\text{A}\)
4. \(0.58~\text{A}\)
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. \(12~\Omega\)