(a) | For a given power level, there is a lower current. |
(b) | Lower current implies less power loss. |
(c) | Transmission lines can be made thinner. |
(d) | It is easy to reduce the voltage at the receiving end using step-down transformers. |
1. | (a), (b), (c) | 2. | (a), (b), (d) |
3. | (b), (c), (d) | 4. | (c), (d) |
A transformer is used to light a \(100~\text{W}\) and \(110~\text{V}\) lamp from a \(220~\text{V}\) main. If the main current is \(0.5~\text{A}\), the efficiency of the transformer is approximately:
1. \(30\%\)
2. \(50\%\)
3. \(90\%\)
4. \(10\%\)
1. | \(800~\Omega\) and \(1.06~\Omega\) | 2. | \(10~\Omega\) and \(500~\Omega\) |
3. | \(800~\Omega\) and \(0.32~\Omega\) | 4. | \(1.06~\Omega\) and \(500~\Omega\) |
A power transmission line feeds input power at \(2300~\text V\) to a step-down transformer with its primary windings having \(4000\) turns. What should be the number of turns in the secondary in order to get output power at \(230~\text V?\)
1. \(200\)
2. \(250\)
3. \(350\)
4. \(400\)