A set of '\(n\)' equal resistors, of value '\(R\)' each, are connected in series to a battery of emf '\(E\)' and internal resistance '\(R\)'. The current drawn is \(I.\) Now, if '\(n\)' resistors are connected in parallel to the same battery, then the current drawn becomes \(10I.\) The value of '\(n\)' is:
1. | \(10\) | 2. | \(11\) |
3. | \(20\) | 4. | \(9\) |
A battery consists of a variable number \(n\) of identical cells (having internal resistance \(r\) each) which are connected in series. The terminals of the battery are short-circuited and the current \(I\) is measured. Which of the graphs shows the correct relationship between \(I\) and \(n?\)
1. | 2. | ||
3. | 4. |
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. | \(\frac{R}{n^2}\) |
A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves:
1. | the potential gradients. |
2. | a condition of no current flow through the galvanometer. |
3. | a condition of cells, galvanometer, and resistances. |
4. | the cells. |
The figure shows a circuit that contains three identical resistors with resistance \(R = 9.0~\Omega\) each, two identical inductors with inductance \(L = 2.0~\text{mH}\) each, and an ideal battery with emf \(\varepsilon = 18~\text{V}\). The current \('i'\) through the battery just after the switch is closed will be:
1. \(0.2~\text{A}\)
2. \(2~\text{A}\)
3. \(4~\text{A}\)
4. \(2~\text{mA}\)
The potential difference between points A and B in the given figure is if the current is flowing from A to B:
1. - 3 V
2. +3 V
3. +6 V
4. +9 V
The potential difference \(V_\mathrm{A}-V_\mathrm{B}\) between the points \(\mathrm{A}\) and \(\mathrm{B}\) in the given figure is:
1. | \(-3~\text{V}\) | 2. | \(+3~\text{V}\) |
3. | \(+6~\text{V}\) | 4. | \(+9~\text{V}\) |
A filament bulb (\(500\) W, \(100\) V) is to be used in a \(230\) V main supply. When a resistance\(R\) is connected in series, the bulb works perfectly and consumes \(500\) W. The value of \(R\) is:
1. | \(230\) | 2. | \(46\) |
3. | \(26\) | 4. | \(13\) |