The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?
|1.||(a) and (d)|
|2.||(a), (b), (c), and (d)|
|3.||(a) and (b)|
An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the ac ammeter reads 6 A. When another alternating current passes through the circuit, the AC ammeter reads 8 A. Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
2. 14 A
3. 10 A
4. 15 A
In the diagram, two sinusoidal voltages of the same frequency are shown. What is the frequency and the phase relationship between the voltages?
|Frequency in Hz||Phase lead of N over M in radians|
A direct current of 5 A is superimposed on an alternating current I = 10 flowing through a wire. The effective value of the resulting current will be:
4. 15 A
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:
The r.m.s. value of the potential difference V shown in the figure is:
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: