Q. No.The potential difference \(V_{A}-V_{B}\) between the points \({A}\) and \({B}\) in the given figure is:
1.
\(-3~\text{V}\)
2.
\(+3~\text{V}\)
3.
\(+6~\text{V}\)
4.
\(+9~\text{V}\)
| 1. | \(\dfrac{a^3R}{3b}\) | 2. | \(\dfrac{a^3R}{2b}\) |
| 3. | \(\dfrac{a^3R}{b}\) | 4. | \(\dfrac{a^3R}{6b}\) |
Two metal wires of identical dimensions are connected in series. If \(\sigma_1~\text{and}~\sigma_2\)
1. \(\dfrac{2\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)
2. \(\dfrac{\sigma_1 +\sigma_2}{2\sigma_1\sigma_2}\)
3. \(\dfrac{\sigma_1 +\sigma_2}{\sigma_1\sigma_2}\)
4. \(\dfrac{\sigma_1 \sigma_2}{\sigma_1+\sigma_2}\)
\({A, B}~\text{and}~{C}\) are voltmeters of resistance \(R,\) \(1.5R\) and \(3R\) respectively as shown in the figure above. When some potential difference is applied between \({X}\) and \({Y},\) the voltmeter readings are \({V}_{A},\) \({V}_{B}\) and \({V}_{C}\) respectively. Then:
| 1. | \({V}_{A} ={V}_{B}={V}_{C}\) | 2. | \({V}_{A} \neq{V}_{B}={V}_{C}\) |
| 3. | \({V}_{A} ={V}_{B}\neq{V}_{C}\) | 4. | \({V}_{A} \ne{V}_{B}\ne{V}_{C}\) |
| 1. | current density | 2. | current |
| 3. | drift velocity | 4. | electric field |
Two cities are \(150~\text{km}\) apart. The electric power is sent from one city to another city through copper wires. The fall of potential per km is \(8~\text{volts}\) and the average resistance per \(\text{km}\) is \(0.5~\text{ohm}.\) The power loss in the wire is:
| 1. | \(19.2~\text{W}\) | 2. | \(19.2~\text{kW}\) |
| 3. | \(19.2~\text{J}\) | 4. | \(12.2~\text{kW}\) |
1. \(4~\Omega\)
2. \(8~\Omega\)
3. \(16~\Omega\)
4. \(2~\Omega\)
| 1. | \(0.5~\Omega\) | 2. | \(0.8~\Omega\) |
| 3. | \(1.0~\Omega\) | 4. | \(0.2~\Omega\) |
| 1. | \(0.2~\text{A}\) | 2. | \(0.1~\text{A}\) |
| 3. | \(2.0~\text{A}\) | 4. | \(1.0~\text{A}\) |
If the voltage across a bulb rated \((220~\text{V}\text-100~\text{W})\) drops by \(2.5\%\) of its rated value, the percentage of the rated value by which the power would decrease is:
1. \(20\%\)
2. \(2.5\%\)
3. \(5\%\)
4. \(10\%\)
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