A generator produces a voltage that is given by V = 240 sin 120 t, where t is in seconds. The frequency and r.m.s. voltage are:
1. | 60 Hz and 240 V |
2. | 19 Hz and 120 V |
3. | 19 Hz and 170 V |
4. | 754 Hz and 70 V |
The variation of the instantaneous current (I) and the instantaneous emf (E) in a circuit are shown in the figure. Which of the following statements is correct?
1. | The voltage lags behind the current by π/2. |
2. | The voltage leads the current by π/2. |
3. | The voltage and the current are in phase. |
4. | The voltage leads the current by π. |
The time required for a 50 Hz sinusoidal alternating current to change its value from zero to the r.m.s. value will be:
1.
2.
3.
4.
The r.m.s. value of the potential difference V shown in the figure is:
1.
2.
3.
4.
The output current versus time curve of a rectifier is shown in the figure.
The average value of the output current in this case will be:
1. | 0 | 2. | \(I_0 \over 2\) |
3. | \(2I_0 \over \pi\) | 4. | \(I_0\) |