In this section, you will find objective questions related to AC Fundamentals which helps to analyze the networks consisting of various alternating current and voltage sources, resistances and inductive, capacitive reactances.

- The form factor in reference to alternating current wave form represents the ratio of
**the R.M.S. value to the average value.** - If the current and voltage are out of phase by 90Β°, thee power is
**Zero.** - The form factor of a 220 V, 50 Hz A.C. waveform is
**1.11.** - If E1 = A sin ππ‘ and E2= A sin (ππ‘βπ)
**then E1 leads E2 byπ½.** - For the waveform shown in figure, average value is
**1.5 A.** - For the above wave the rms value will be
**1.528 A.** - Two sinusoidal quantities are said to be phase quadrature, when their phase difference is
**ππΒ°.** - The equation for 25 cycles current sine wave having rms value of 30 amperes, will be
**42.4 sin50Οt.** - R.M.S value of a current given by π=10+5 cos (628π‘+90Β°) is
**10.6A** - What is the rms value of rectangular voltage wave with an amplitude of 10 V?
**10V.** - The mean value of a.c related to peak value of a.c by the equation is π°π= ππ°ππ .
- In above case , the value of direct current which produces in the same conductor the same amount of heat in the same time will be
**141 V.** - The current in a circuit follows the law π=100sinππ‘, If the frequency is 25 Hz how long will it take for the current to rise to 50 amperes? πππππ sec.
- The voltage π£=90cos(ππ‘β161.5Β°) may be represented as sine function by πππ¬π’π§(ππβππ.πΒ°).
- The equation of emf is given by =π°πβ(ππ+πππππ) .
- In above problem the frequency in hertz is
**ππ .** - The negative maximum of a cosine waveform occurs at
**180Β°.** - The RMS value of sinusoidal 200 V peak to peak wave is
**πππβπ v. ???** - The positive maximum of a sine wave occurs at ππΒ°

- In figure 4 the combined impedance of the parallel circuits equals
**120 V.**

- For the same peak value of voltage, which waveform will have the least rms value?
**Triangular wave.** - For the same peak value of voltage, which waveform will have the highest rms value?
**Square wave.** - Which wave has the highest value of form factor?
**Half wave rectified sine wave.** - Which wave has the least value of form factor?
**Square wave.** - Which of the following waves has form factor of 1.0?
**Square wave.** - If one cycle of ac waveform occurs every milli-second, the frequency will be
**1000Hz.** - Which of the following frequencies has the longest period?
**10kHz.** - RMS value and the mean value is the same in case of
**Square wave.** - If emf in a circuit is given by π=100sin628π‘ then maximum value of voltage and frequency are
**100V 100Hz.**

- If a wave form more peaky than a sine wave, the form factor
**will be more than 1.11.** - For a triangular wave, the form factor is
**1.15.** - For a square wave, the form factor is
**1.0.** - The equation of alternating current is π=42.42sin628π‘. the average value of current is
**27A.** - For the voltage waveform shown in figure 5 the rms value of voltage will be βππ π πππ.
- The average value of the above voltage is ππ π πππ.
- The peak factor for the above voltage is πβπ .

- The form factor for the above voltage is
**βππ.****Questions 38 to 40 refer to the following data:**

A current has following steady values in amperes for equal intervals of time changing

simultaneously from one to the next 0, 10, 20, 30, 20, 10, 0, -10, -20, -30, -20, -10, -0. - The rms value of the current will be
**17.8 A.** - The form factor will be
**1.187.** - The peak value of a wave is
**Maximum valuer.m.s value**

- In the above case the value of which parameter for full sine wave will be more?
**Average value**. - An alternating voltage π = 200 π ππ 314π‘ is applied to a device which offers an ohmic

resistance of 200Ξ© to the flow of current in one direction while entirely preventing the

flow in the opposite direction. The value of current will be**5 A. ??** - In the above case, the average value of the current will be
**3.18 A.** - When the sole purpose of the alternating current is to produce heat, the selection of

conductor is based on**rms value of current.** - The r.m.s value of a.c. is related to peak value of a.c. by the equation
**π°π = βπ I r.m.s.** - The form factor of dc supply voltage is always
**Unity.** - What is the angle in the NE quadrant corresponding to a rms value of the quantity, π¦ =π¦πππ₯ π ππππ‘?
**π π**.

- What is the angle in NE quadrant corresponding to the average value of the quantity,

π¦ = π¦πππ₯π ππππ‘?**0.69 rad.** - Two currents represented by π1 = 50 sin ππ‘ , π12 = 100 sin(ππ‘ + 45 Β°) are fed into

a common conductor. The rms value of the current will be**between 50 A and 100 A.**